Display device with touch detection function and electronic apparatus

ABSTRACT

A display device with a touch detection function includes a control device that performs, in normal operation mode, image display control so as to exhibit an image display function of a display function layer based on an image signal and performs touch detection control; a touch detecting unit that detects, in the normal operation mode, a position of an object in proximity to or in contact with the touch detection electrode based on a detection signal transmitted from the touch detection electrode; and a touch-detection controller that detects, in sleep mode, the proximity of the object to or the contact thereof with the touch detection electrode. When the touch-detection controller detects the proximity of the object to or the contact thereof with the touch detection electrode in the sleep mode, the control device controls a pixel electrode to a predetermined potential, and thereafter supplies a touch drive signal to a drive electrode.

CROSS REFERENCES TO RELATED APPLICATIONS

The present application is a continuation of U.S. patent applicationSer. No. 14/298,527, filed on Jun. 6, 2014, which application claimspriority to Japanese Priority Patent Application JP 2013-123208 filed inthe Japan Patent Office on Jun. 11, 2013, the entire content of which ishereby incorporated by reference.

BACKGROUND

1. Technical Field

The present disclosure relates to a display device with a touchdetection function and an electronic apparatus that are capable ofdetecting an external proximity object.

2. Description of the Related Art

In recent years, attention is paid to a touch detection device, which isreferred to as a so-called touch panel, capable of detecting an externalproximity object. The touch panel is used for a display device with atouch detection function in which it is mounted on the display devicesuch as a liquid crystal display device (so-called on-cell type) or isintegrated with the display device (so-called in-cell type). The displaydevice with a touch detection function displays various button imagesand the like on the display device, and this allows information inputusing the touch panel instead of normal mechanical buttons. The use ofthe display device with a touch detection function having such a touchpanel tends to increase in portable information devices such as mobilephones and tablets as well as computers because an input device such asa keyboard, a mouse, or a keypad is not required.

The display device with a touch detection function used in electronicapparatuses such as mobile phones and tablets preferably has a normaloperation mode for performing image display and touch detection and asleep mode for stopping image display and suspending operation of unitswhen no operation is input for a given time in order to reduce powerconsumption.

For example, Japanese Patent Application Laid-open Publication No.2011-44004 (JP-A-2011-44004) describes a capacitive touch panel. When aninput-operation position detecting unit that operates in a normal modedetects no input operation for a predetermined period, the touch panelshifts to a sleep mode in which the operation of the input-operationposition detecting unit is suspended and a plurality of capacity-timeconvertors and an input determination unit are intermittently operated.When the input determination unit that intermittently operates in thesleep mode determines that there is an input operation, the touch panelshifts to the normal mode in which the input-operation positiondetecting unit operates.

The capacitive touch panel described in JP-A-2011-44004 mounted on adisplay constitutes an on-cell type display device with a touchdetection function in a manner mounted on a display, but does notconstitute an in-cell type display device with a touch detectionfunction.

The in-cell type display device with a touch detection function has aproblem specific to the in-cell type such that burn-in may occur on adisplay screen when shifting from the sleep mode to the normal operationmode, and it is therefore preferred to suppress the burn-in.

For the capacitive touch panel described in JP-A-2011-44004, the problemspecific to the in-cell type such that burn-in may occur on the displayscreen is not considered because the capacitive touch panel describedtherein constitutes the on-cell type display device with a touchdetection function but does not constitute the in-cell type displaydevice with a touch detection function.

The present disclosure has been made to solve the problems, and it is anobject of the present disclosure to provide a display device with atouch detection function and an electronic apparatus that are capable ofpreventing burn-in occurring on a display screen.

SUMMARY

A display device with a touch detection function according to thepresent disclosure has a normal operation mode for performing imagedisplay and touch detection and a sleep mode for performing touchdetection without performing the image display. The display device witha touch detection function includes: a display area in which a pluralityof pixel electrodes are arranged in a matrix on a substrate; a driveelectrode that is arranged opposite to the pixel electrodes and isdivided into a plurality of portions; a touch detection electrode thatis arranged opposite to the drive electrode and forms a capacitance withthe drive electrode; a display function layer that has an image displayfunction for displaying an image in the display area; a control devicethat performs image display control, in the normal operation mode, so asto apply a display drive voltage between the pixel electrode and thedrive electrode based on an image signal to exhibit the image displayfunction of the display function layer, and performs touch detectioncontrol so as to supply a touch drive signal to the drive electrode; atouch detecting unit that detects, in the normal operation mode, aposition of an object in proximity to or in contact with the touchdetection electrode based on a detection signal transmitted from thetouch detection electrode; and a touch-detection controller thatdetects, in the sleep mode, the proximity of the object to or thecontact thereof with the touch detection electrode. When thetouch-detection controller detects the proximity of the object to or thecontact thereof with the touch detection electrode in the sleep mode,the control device controls the pixel electrode to a predeterminedpotential, and thereafter supplies the touch drive signal to the driveelectrode.

An electronic apparatus according to the present disclosure is providedwith the display device with a touch detection function, and correspondsto, for example, television devices, digital cameras, personalcomputers, video cameras, or portable electronic apparatuses such asmobile phones.

Additional features and advantages are described herein, and will beapparent from the following Detailed Description and the figures.

BRIEF DESCRIPTION OF THE FIGURES

FIG. 1 is a block diagram of a configuration example of a display devicewith a touch detection function according to a first embodiment;

FIG. 2 is an explanatory diagram for explaining a basic principle of amutual capacitance type touch detection method and illustrating a statewhere a finger is not in contact with or in proximity to the device;

FIG. 3 is an explanatory diagram illustrating an example of anequivalent circuit in a state where a finger is not in contact with orin proximity to the device as illustrated in FIG. 2;

FIG. 4 is an explanatory diagram for explaining the basic principle ofthe mutual capacitance type touch detection method and illustrating astate where a finger is in contact with or in proximity to the device;

FIG. 5 is an explanatory diagram illustrating an example of theequivalent circuit in a state where a finger is in contact with or inproximity to the device as illustrated in FIG. 4;

FIG. 6 is a diagram of examples of waveforms of a drive signal and atouch detection signal;

FIG. 7 is a diagram of an example of a module that mounts thereon thedisplay device with a touch detection function according to the firstembodiment;

FIG. 8 is a diagram of another example of the module that mounts thereonthe display device with a touch detection function according to thefirst embodiment;

FIG. 9 is a diagram of an example of a booster circuit;

FIG. 10 is a diagram of an example of the booster circuit;

FIG. 11 is a diagram of an example of a charge pump;

FIG. 12 is a diagram of an example of the charge pump;

FIG. 13 is a cross-sectional view of a schematic cross-sectionalstructure of a display unit with a touch detection function according tothe first embodiment;

FIG. 14 is a diagram of an example of a control device for the displaydevice with a touch detection function according to the firstembodiment;

FIG. 15 is a circuit diagram of a pixel array of the display unit with atouch detection function according to the first embodiment;

FIG. 16 is a schematic diagram for explaining a relation between asource driver and pixel signal lines in the module that mounts thereonthe display device with a touch detection function according to thefirst embodiment;

FIG. 17 is a perspective view of a configuration example of driveelectrodes and touch detection electrodes of the display unit with atouch detection function according to the first embodiment;

FIG. 18 is a schematic diagram of an operation example of touchdetection in the display device with a touch detection functionaccording to the first embodiment;

FIG. 19 is a schematic diagram of an operation example of touchdetection in the display device with a touch detection functionaccording to the first embodiment;

FIG. 20 is a schematic diagram of an operation example of touchdetection in the display device with a touch detection functionaccording to the first embodiment;

FIG. 21 is a block diagram of a drive signal generating unit of a driveelectrode driver according to the first embodiment;

FIG. 22 is a block diagram of the drive electrode driver according tothe first embodiment;

FIG. 23 is a block diagram of a drive unit of the drive electrode driveraccording to the first embodiment;

FIG. 24 is a block diagram of an arrangement example of selectionswitches of the drive electrode driver according to the firstembodiment;

FIG. 25 is an explanatory diagram for explaining a basic principle ofself-capacitance type touch detection and illustrating a state where afinger is not in contact with or in proximity to the device;

FIG. 26 is an explanatory diagram for explaining a basic principle ofthe self-capacitance type touch detection and illustrating a state wherea finger is not in contact with or in proximity to the device;

FIG. 27 is an explanatory diagram for explaining a basic principle ofthe self-capacitance type touch detection and illustrating a state wherea finger is in contact with or in proximity to the device;

FIG. 28 is an explanatory diagram for explaining a basic principle ofthe self-capacitance type touch detection and illustrating a state wherea finger is in contact with or in proximity to the device;

FIG. 29 is an explanatory diagram illustrating a detection circuit;

FIG. 30 is an explanatory diagram illustrating an equivalent circuit ofthe detection circuit in FIG. 29;

FIG. 31 is a diagram of an example of waveforms of the detection circuitin FIG. 29;

FIG. 32 is a diagram schematically illustrating operation of the displaydevice with a touch detection function in one frame period (1F);

FIG. 33 is a timing chart of operation of the display device with atouch detection function;

FIG. 34 is a timing chart of display operation of the display devicewith a touch detection function;

FIG. 35 is a timing chart of touch detection operation of the displaydevice with a touch detection function;

FIG. 36 is a timing chart of memory write and memory read in the displaydevice with a touch detection function;

FIG. 37 is another timing chart of the memory write and the memory readin the display device with a touch detection function;

FIG. 38 is a timing chart of touch detection operation of the displaydevice with a touch detection function;

FIG. 39 is a flowchart of operation of the display device with a touchdetection function in sleep mode;

FIG. 40 is an explanatory diagram illustrating a timing waveform exampleof the display device with a touch detection function;

FIG. 41 is a timing chart of display operation and touch detectionoperation in a display device with a touch detection function accordingto a comparative example;

FIG. 42 is a diagram schematically illustrating operation of the displaydevice with a touch detection function when a touch detection scanningis performed at a speed four times as high as that of display scanning;

FIG. 43 is a diagram schematically illustrating operation of the displaydevice with a touch detection function when a size of a partialdetection region RT is set to half of a size of a partial display regionRD;

FIG. 44 is a diagram schematically illustrating operation of the displaydevice with a touch detection function when data in two partial displayregions RD are temporarily stored;

FIG. 45 is a diagram schematically illustrating an example of touchdetection operation in the display device with a touch detectionfunction;

FIG. 46 is a diagram schematically illustrating an example of the touchdetection operation in the display device with a touch detectionfunction;

FIG. 47 is a diagram schematically illustrating an example of the touchdetection operation in the display device with a touch detectionfunction;

FIG. 48 is a diagram of an example of a touch detecting unit of adisplay device with a touch detection function according to a secondembodiment;

FIG. 49 is a diagram of a detecting unit of the display device with atouch detection function according to the second embodiment;

FIG. 50 is a diagram of the detecting unit of the display device with atouch detection function according to the second embodiment;

FIG. 51 is a diagram of a display device with a touch detection functionaccording to a third embodiment;

FIG. 52 is a diagram of an example of a control device of a displaydevice with a touch detection function according to a fourth embodiment;

FIG. 53 is a block diagram of a drive unit of a drive electrode driveraccording to the fourth embodiment;

FIG. 54 is a block diagram of an arrangement example of selectionswitches of the drive electrode driver according to the fourthembodiment;

FIG. 55 is a block diagram of a drive unit of a drive electrode driverin a display device with a touch detection function according to a fifthembodiment;

FIG. 56 is a block diagram of an arrangement example of selectionswitches of the drive electrode driver in the display device with atouch detection function according to the fifth embodiment;

FIG. 57 is a diagram of an example of a module that mounts thereon adisplay device with a touch detection function according to a sixthembodiment;

FIG. 58 is a timing chart of operation of the display device with atouch detection function according to the sixth embodiment;

FIG. 59 is a cross-sectional view of a schematic cross-sectionalstructure of a display unit with a touch detection function according toa modification;

FIG. 60 is a diagram of an example of an electronic apparatus to whichthe display device with a touch detection function according to one ofthe embodiments and modifications thereof is applied;

FIG. 61 is a diagram of an example of an electronic apparatus to whichthe display device with a touch detection function according to one ofthe embodiments and modifications thereof is applied;

FIG. 62 is a diagram of an example of the electronic apparatus to whichthe display device with a touch detection function according to one ofthe embodiments and modifications thereof is applied;

FIG. 63 is a diagram of an example of an electronic apparatus to whichthe display device with a touch detection function according to one ofthe embodiments and modifications thereof is applied;

FIG. 64 is a diagram of an example of an electronic apparatus to whichthe display device with a touch detection function according to one ofthe embodiments and modifications thereof is applied;

FIG. 65 is a diagram of an example of an electronic apparatus to whichthe display device with a touch detection function according to one ofthe embodiments and modifications thereof is applied;

FIG. 66 is a diagram of an example of the electronic apparatus to whichthe display device with a touch detection function according to one ofthe embodiments and modifications thereof is applied;

FIG. 67 is a diagram of an example of the electronic apparatus to whichthe display device with a touch detection function according to one ofthe embodiments and modifications thereof is applied;

FIG. 68 is a diagram of an example of the electronic apparatus to whichthe display device with a touch detection function according to one ofthe embodiments and modifications thereof is applied;

FIG. 69 is a diagram of an example of the electronic apparatus to whichthe display device with a touch detection function according to one ofthe embodiments and modifications thereof is applied;

FIG. 70 is a diagram of an example of the electronic apparatus to whichthe display device with a touch detection function according to one ofthe embodiments and modifications thereof is applied;

FIG. 71 is a diagram of an example of the electronic apparatus to whichthe display device with a touch detection function according to one ofthe embodiments and modifications thereof is applied; and

FIG. 72 is a diagram of an example of an electronic apparatus to whichthe display device with a touch detection function according to one ofthe embodiments and modifications thereof is applied.

DETAILED DESCRIPTION

Exemplary embodiments of the present disclosure will be explained indetail below with reference to the accompanying drawings. The presentdisclosure is not limited by the contents described in the followingembodiments. In addition, the components described as follows includethose which can be easily conceived by persons skilled in the art andthose which are substantially equivalent. Moreover, the componentsdescribed as follows can be arbitrarily combined with each other. Theexplanation is performed in the following order.

1. Embodiments (Display Device with Touch Detection Function)

-   -   1-1. First Embodiment    -   1-2. Second Embodiment    -   1-3. Third Embodiment    -   1-4. Fourth Embodiment    -   1-5. Fifth Embodiment    -   1-6. Sixth Embodiment

2. Application Examples (Electronic Apparatuses)

Examples of applying the display device with a touch detection functionaccording to the embodiments to electronic apparatuses.

3. Configuration of Present Disclosure

1-1. First Embodiment Configuration Example Entire Configuration Example

FIG. 1 is a block diagram of a configuration example of a display devicewith a touch detection function according to a first embodiment. Adisplay device with a touch detection function 1 includes a display unitwith a touch detection function 10, a control unit 11, a gate driver 12,a source driver 13, a source selector 13S, a drive electrode driver 14,a touch detection unit 40, a touch-detection controller 100, and a gatedriver 100D. The display device with a touch detection function 1 is adisplay device in which the display unit with a touch detection function10 has a built-in touch detection function. The display unit with atouch detection function 10 is a so-called in-cell type device in whicha liquid crystal display unit 20 using a liquid crystal display elementas a display element and a capacitive-type touch detecting unit 30 areintegrated. The display unit with a touch detection function 10 may be aso-called on-cell type device in which the capacitive-type touchdetecting unit 30 is mounted on the liquid crystal display unit 20 usingthe liquid crystal display element as a display element.

Characteristics

The display device with a touch detection function 1 has a normaloperation mode for performing image display and touch detection and asleep mode for performing touch detection without performing the imagedisplay. When no touch operation is detected for a given period in thenormal operation mode, the display device with a touch detectionfunction 1 shifts to the sleep mode. When a predetermined gesture isdetected in the sleep mode, the display device with a touch detectionfunction 1 shifts to the normal operation mode.

The display device with a touch detection function 1 is configured sothat, in the normal operation mode, the control unit 11, the gate driver12, the source driver 13, the source selector 13S, the drive electrodedriver 14, and the touch detection unit 40 mainly operate. In the normaloperation mode, an application processor (host CPU, not illustrated) forexecuting an operating system program or the like to control an entireelectronic apparatus and a backlight (not illustrated) for irradiatinglight from the back of the display device with a touch detectionfunction 1 also operate. Meanwhile, the display device with a touchdetection function 1 is configured so that, in the sleep mode, thecontrol unit 11, the source driver 13, the source selector 13S, thedrive electrode driver 14, the touch detection unit 40, thetouch-detection controller 100, and the gate driver 100D mainly operate.In the sleep mode, the application processor, the backlight, and thelike do not operate. This enables the electronic apparatus to reducepower consumption.

In the normal operation mode, the display device with a touch detectionfunction 1 detects a touch operation using mutual capacitance methodbetween a drive electrode COML explained later and a touch detectionelectrode TDL explained later. In the sleep mode, the display devicewith a touch detection function 1 detects presence or absence of touchdetection using self-capacitance method of the touch detection electrodeTDL. When the presence of a touch is detected, the display device with atouch detection function 1 detects touch coordinates and a gesture usingthe mutual capacitance method between the drive electrode COML and thetouch detection electrode TDL, and shifts to the normal operation modewhen a predetermined gesture is detected.

The display device with a touch detection function 1 also includes thegate driver 12 that operates in the normal operation mode and the gatedriver 100D that operates in the sleep mode. The display device with atouch detection function 1 is constantly supplied with a predeterminedpower supply voltage (hereinafter, Vcc) from a battery (notillustrated), a main substrate (not illustrated) of the electronicapparatus, or the like. In the normal operation mode, the display devicewith a touch detection function 1 causes the gate driver 12 to operateat a power supply voltage (hereinafter, Vdd) at which the power supplyvoltage Vcc is boosted by a booster circuit explained later in order tocause a liquid crystal display element in the liquid crystal displayunit 20 to operate at a high speed and perform fast image display. Inother words, the gate driver 12 is a circuit that operates at the powersupply voltage Vdd. In the sleep mode, on the other hand, the displaydevice with a touch detection function 1 suspends the booster circuit inorder to reduce power consumption and operates the gate driver 100D atthe power supply voltage Vcc. In other words, the gate driver 100D is acircuit that operates at the power supply voltage Vcc.

Overview of Units

The display unit with a touch detection function 10 is a display devicehaving a built-in touch detection function. The display unit with atouch detection function 10 includes the liquid crystal display unit 20and the touch detecting unit 30. The liquid crystal display unit 20 is adevice that sequentially scans and displays horizontal lines one by oneaccording to a scan signal Vscan supplied from the gate driver 12, asexplained later. At this time, the liquid crystal display unit 20 isconfigured to sequentially scan horizontal lines one by one and displaythe horizontal line in each partial display region RD obtained byvertically dividing a display screen into 10 equal parts. The touchdetecting unit 30 operates based on a basic principle of capacitivetouch detection explained later and outputs a touch detection signalVdet. The touch detecting unit 30 is configured to perform sequentialscan according to a drive signal VcomAC supplied from the driveelectrode driver 14 and perform touch detection as explained later.

The control unit 11 is a circuit that supplies a control signal to thegate driver 12, the source driver 13, the drive electrode driver 14, andthe touch detection unit 40 based on an externally supplied video signalVdisp to control so that these units operate in synchronization with oneanother. The control device according to the present disclosure includesthe control unit 11, the gate driver 12, the source driver 13, and thedrive electrode driver 14.

The control unit 11 has a memory 11 a that temporarily stores thereinvideo information of the video signal Vdisp. A storage capacity of thememory 11 a corresponds to a data amount of one-tenth of videoinformation for one frame in this example. In other words, for example,when a vertical display resolution is 1280 pixels, the memory 11 a isconfigured to store video information for 128 lines.

The memory 11 a writes the video information for the video signal Vdispsupplied from a host device in synchronization with a verticalsynchronization signal Vsync and a horizontal synchronization signalHsync which are also supplied from the host device. The memory 11 a isconfigured to read the stored video information in synchronization withan internal clock of the display device with a touch detection function1 at a speed higher than that of the write. Specifically, the memory 11a sequentially writes data of one-tenth of the video information for oneframe by each one horizontal line, and then sequentially writes nextone-tenth data by each one horizontal line in the above manner whileoverwriting the previous one-tenth data. The memory 11 a sequentiallyreads the written data by each one horizontal line at a speed higherthan that of the write before the data is erased by being overwritten.The display device with a touch detection function 1 performs a displaybased on the read data for each partial display region RD obtained byvertically dividing the display screen into 10 equal parts, as explainedlater.

The gate driver 12 has a function of sequentially selecting onehorizontal line targeted for display drive of the display unit with atouch detection function 10, based on the control signal supplied fromthe control unit 11. Specifically, the gate driver 12 applies the scansignal Vscan to gates of TFT elements Tr in pixels Pix via a scan signalline GCL, as explained later, to thereby sequentially select one line(one horizontal line), as a target for display drive, from among thepixels Pix formed in a matrix on the liquid crystal display unit 20 ofthe display unit with a touch detection function 10.

The source driver 13 is a circuit that supplies a pixel signal Vpix toeach pixel Pix (sub-pixels SPix), explained later, of the display unitwith a touch detection function 10 based on the control signal suppliedfrom the control unit 11. As explained later, the source driver 13generates a pixel signal, in which the pixel signals Vpix of a pluralityof sub-pixels SPix in the liquid crystal display unit 20 aretime-division multiplexed, from the video signal Vdisp for onehorizontal line, and supplies the generated pixel signal to the sourceselector 13S. The source driver 13 also generates a switch controlsignal Vsel required to separate the pixel signals Vpix multiplexed onan image signal Vsig therefrom, and supplies the generated signal withthe pixel signal Vpix to the source selector 13S. The source selector13S enables reduction in the number of wirings between the source driver13 and the control unit 11.

The drive electrode driver 14 is a circuit that supplies the touch drivesignal detection (touch drive signal; hereinafter, “drive signal”)VcomAC and a display drive voltage VcomDC being a voltage for display toa drive electrode COML, explained later, of the display unit with atouch detection function 10 based on the control signal supplied fromthe control unit 11. Specifically, the drive electrode driver 14 appliesthe display drive voltage VcomDC to the drive electrode COML in adisplay period Pd, as explained later. In a touch detection period Pt,the drive electrode driver 14 applies the drive signal VcomAC to thedrive electrode COML targeted for touch detection operation, and appliesthe display drive voltage VcomDC to any other drive electrodes COML, asexplained later. At this time, the drive electrode driver 14 drives thedrive electrodes COML for each block (partial detection region RT,explained later) that includes a predetermined number of driveelectrodes COML. Furthermore, the drive electrode driver 14 isconfigured so as to enable change the frequency of the drive signalVcomAC, as explained later.

The touch detection unit 40 is a circuit that detects the presence orabsence of a touch (the contact state) performed on the touch detectingunit 30 based on the control signal supplied from the control unit 11and the touch detection signal Vdet supplied from the touch detectingunit 30 of the display unit with a touch detection function 10, and thatcalculates coordinates and the like of the touch in a touch detectionarea when the presence of a touch is detected. The touch detection unit40 includes a touch-detection-signal amplification unit (hereinafter, anamplifier) 42, an analog-to-digital (A/D) convertor 43, a signalprocessor 44, a coordinate extractor 45, a detection-timing controller46.

The amplifier 42 amplifies the touch detection signal Vdet supplied fromthe touch detecting unit 30. The amplifier 42 may include a low-passanalog filter that removes a high frequency component (noise component)contained in the touch detection signal Vdet, extracts touch components,and outputs the touch components.

The touch-detection controller 100 operates in the sleep mode, and firstdetects the presence or absence of a touch (the contact state) performedon the touch detecting unit 30 of the display unit with a touchdetection function 10 using the self-capacitance method. When thepresence of a touch is detected, the touch-detection controller 100causes the control unit 11 to drive the gate driver 100D, and detectstouch coordinates and a gesture using the mutual capacitance method. Thegate driver 100D has a function of sequentially selecting one horizontalline targeted for drive of the display unit with a touch detectionfunction 10 based on the control signal supplied from the control unit11. The touch-detection controller 100 detects touch coordinates and agesture or so in the touch detection area of the touch detecting unit 30based on the touch detection signal Vdet supplied from the touchdetecting unit 30 in the display unit with a touch detection function10. When a predetermined gesture is detected, then the touch-detectioncontroller 100 causes the display device with a touch detection function1 to shift to the normal operation mode.

Basic Principle of Mutual Capacitance Type Touch Detection

The touch detecting unit 30 operates based on the basic principle ofmutual capacitance type touch detection, and outputs a touch detectionsignal Vdet. The basic principle of the mutual capacitance type touchdetection in the display device with a touch detection function 1according to the present embodiment will be explained below withreference to FIG. 1 to FIG. 6. FIG. 2 is an explanatory diagram forexplaining the basic principle of the mutual capacitance type touchdetection and illustrating a state where a finger is not in contact withor in proximity to the device. FIG. 3 is an explanatory diagramillustrating an example of an equivalent circuit in a state where afinger is not in contact with or in proximity to the device asillustrated in FIG. 2. FIG. 4 is an explanatory diagram for explainingthe basic principle of the mutual capacitance type touch detectionmethod and illustrating a state where a finger is in contact with or inproximity to the device. FIG. 5 is an explanatory diagram illustratingan example of the equivalent circuit in a state where a finger is incontact with or in proximity to the device as illustrated in FIG. 4.FIG. 6 is a diagram of examples of waveforms of a drive signal and atouch detection signal.

For example, as illustrated in FIG. 2, a capacitive element C1 includesa pair of electrodes, a drive electrode E1 and a touch detectionelectrode E2, which are arranged opposite to each other across adielectric body D. As illustrated in FIG. 3, the capacitive element C1is coupled at one end to an alternating-current (AC) signal source(drive signal source) S and is coupled at the other end to a voltagedetector (touch detecting unit) DET. The voltage detector DET is anintegration circuit included in, for example, the amplifier 42illustrated in FIG. 1.

When an AC square wave Sg of a predetermined frequency (e.g., aboutseveral kHz to several hundreds of kHz) is applied from the AC signalsource S to the drive electrode E1 (one end of the capacitive elementC1), an output waveform (touch detection signal Vdet) appears via thevoltage detector DET coupled to the touch detection electrode E2 (theother end of the capacitive element C1). The AC square wave Sgcorresponds to the drive signal VcomAC explained later.

In a state (non-contact state) where a finger is not in contact (or inproximity), as illustrated in FIG. 2 and FIG. 3, a current I₀ accordingto a capacitance of the capacitive element C1 flows in the capacitiveelement C1 in association with charge and discharge thereof. The voltagedetector DET illustrated in FIG. 5 converts the fluctuation of thecurrent I₀ according to the AC square wave Sg into the fluctuation of avoltage (waveform V₀ indicated by solid line).

Meanwhile, in a state (contact state) where a finger is in contact (orin proximity), as illustrated in FIG. 4, a capacitance C2 formed by thefinger is in contact with or in proximity to the touch detectionelectrode E2, and a capacitance for a fringe between the drive electrodeE1 and the touch detection electrode E2 is thereby blocked to act as acapacitive element C1′ with a capacitance smaller than that of thecapacitive element C1. It is understood from the equivalent circuitillustrated in FIG. 5 that a current I₁ flows in the capacitive elementC1′. As illustrated in FIG. 6, the voltage detector DET converts thefluctuation of the current I₁ according to the AC square wave Sg intothe fluctuation of a voltage (waveform V₁ indicated by dotted line). Inthis case, the amplitude of the waveform V₁ becomes lower as comparedwith that of the waveform V₀. Thereby, an absolute value |ΔV| of avoltage difference between the waveform V₀ and the waveform V₁ changesaccording to the influence of an object approaching from the outsidesuch as a finger. To accurately detect the absolute value |ΔV| of thevoltage difference between the waveform V₀ and the waveform V₁, it ismore preferable that the voltage detector DET operates by providingperiods Reset in which charge and discharge of the capacitor are resetin synchronization with the frequency of the AC square wave Sg throughswitching in the circuit.

The touch detecting unit 30 illustrated in FIG. 1 is configured tosequentially scan detection blocks one by one and perform touchdetection according to the drive signal Vcom (drive signal VcomAC,explained later) supplied from the drive electrode driver 14.

The touch detecting unit 30 is configured to output the touch detectionsignals Vdet for each detection block from a plurality of touchdetection electrodes TDL, explained later, via the voltage detector DETillustrated in FIG. 3 or FIG. 5 to be supplied to the A/D convertor 43of the touch detection unit 40.

The A/D convertor 43 is a circuit that samples each analog signal outputfrom the amplifier 42 at a timing synchronized with the drive signalVcomAC and converts the sampled signal into a digital signal.

The signal processor 44 includes a digital filter that reduces anyfrequency component (noise component), included in the output signal ofthe A/D convertor 43, other than the frequency at which the drive signalVcomAC is sampled. The signal processor 44 is a logic circuit thatdetects the presence or absence of a touch performed on the touchdetecting unit 30 based on the output signal of the A/D convertor 43.The signal processor 44 performs a process of extracting only a signalfor a difference caused by the finger. The signal for the differencecaused by the finger is the absolute value |ΔV| of the differencebetween the waveform V₀ and the waveform V₁. The signal processor 44 mayperform operation of averaging absolute values |ΔV| per one detectionblock to calculate an average value of the absolute values |ΔV|. Thisenables the signal processor 44 to reduce the influence caused by thenoise. The signal processor 44 compares the detected signal for thedifference caused by the finger with a predetermined threshold voltage,and determines, if the detected signal is less than the thresholdvoltage, that the external proximity object is in the non-contact state.Meanwhile, the signal processor 44 compares the detected digital voltagewith the predetermined threshold voltage, and determines, if it is thethreshold voltage or more, that the external proximity object is in thecontact state. In this way, the touch detection unit 40 becomes capableof performing touch detection.

The coordinate extractor 45 is a logic circuit that calculates, when thesignal processor 44 detects a touch, touch panel coordinates of thetouch. The detection-timing controller 46 controls so that the A/Dconvertor 43, the signal processor 44, and the coordinate extractor 45operate in synchronization with one another. The coordinate extractor 45outputs the touch panel coordinates as a signal output Vout.

Module

FIG. 7 is a diagram of an example of a module that mounts thereon thedisplay device with a touch detection function according to the firstembodiment. As illustrated in FIG. 7, the display device with a touchdetection function 1 includes a pixel substrate 2 (thin film transistor(TFT) substrate 21) and a flexible printed wiring board T, which areexplained later. The pixel substrate 2 (TFT substrate 21) is providedwith Chip On Glass (COG) 19, and has a display area Ad of the liquidcrystal display unit and a frame Gd formed thereon. The COG 19 is a chipof an IC driver mounted on the TFT substrate 21 and is a control devicewith built-in circuits, such as the control unit 11 and the sourcedriver 13 illustrated in FIG. 1, required for display operation. In thepresent embodiment, the source driver 13 and the source selector 13S areformed on the TFT substrate 21. The source driver 13 and the sourceselector 13S may be built into the COG 19. Drive electrode scanningunits 14A and 14B which are part of the drive electrode driver 14 areformed on the TFT substrate 21. The gate driver 12 is formed on the TFTsubstrate 21 as gate drivers 12A and 12B. The gate driver 100D is alsoformed on the TFT substrate 21. The display device with a touchdetection function 1 may incorporate circuits such as the driveelectrode scanning units 14A and 14B, the gate driver 12, and the gatedriver 100D in the COG 19.

As illustrated in FIG. 7, a drive electrode block B of the driveelectrodes COML and the touch detection electrodes TDL are formed so asto three-dimensionally intersect each other in a direction perpendicularto the surface of the TFT substrate 21.

The drive electrode COML is divided into a plurality of stripe-shapedelectrode patterns extending along one direction. When performing touchdetection operation, the drive electrode driver 14 sequentially suppliesthe drive signal VcomAC to each of the electrode patterns. Thestripe-shaped electrode patterns of the drive electrode COMLsimultaneously supplied with the drive signal VcomAC correspond to thedrive electrode block B illustrated in FIG. 7. The drive electrodeblocks B (drive electrodes COML) are formed in a long-side direction ofthe display unit with a touch detection function 10, and the touchdetection electrodes TDL, explained later, are formed in a short-sidedirection of the display unit with a touch detection function 10.Outputs of the touch detection electrodes TDL are provided on theshort-side side of the display unit with a touch detection function 10and are coupled to a touch IC 110 mounted on the flexible printed wiringboard T via the flexible printed wiring board T. The touch IC 110includes the touch detection unit 40 and the touch-detection controller100. In this way, the touch IC 110 is mounted on the flexible printedwiring board T and is coupled to each of the touch detection electrodesTDL arranged in parallel. The flexible printed wiring board T may be anyterminal and is not therefore limited to the flexible printed wiringboard, and, in this case, the touch IC 110 is provided outside themodule.

A drive signal generating unit, explained later, is built in the COG 19.The source selector 13S is formed using a TFT element near the displayarea Ad on the TFT substrate 21. A large number of pixels Pix, explainedlater, are arranged in a matrix (in the form of rows and columns) in thedisplay area Ad. The frames Gd and Gd are areas where no pixels Pix arearranged when the surface of the TFT substrate 21 is viewed from thedirection perpendicular thereto. The gate driver 12, the gate driver100D, and the drive electrode scanning units 14A and 14B of the drivedriver 14 are arranged in the frames Gd and Gd.

The gate driver 12 includes the gate drivers 12A and 12B and is formedon the TFT substrate 21 using the TFT element. The gate drivers 12A and12B are configured so as to be capable of driving the display area Adfrom both sides of the display area Ad where the sub-pixels SPix(pixels), explained later, are arrange in a matrix. In the followingexplanation, the gate driver 12A is described as a first gate driver 12Aand the gate driver 12B is described as a second gate driver 12B. Scanlines GCL, explained later, are arranged between the first gate driver12A and the second gate driver 12B. Therefore, the scan lines GCLexplained later are provided so as to extend along a direction parallelto the extending direction of the drive electrodes COML in the directionperpendicular to the surface of the TFT substrate 21.

The gate driver 100D is formed on the TFT substrate 21 using a TFTelement. The gate driver 100D is configured so as to be capable ofdriving the display area Ad, from one side, where the sub-pixels SPix(pixels) explained later are arrange in the matrix.

The drive electrode scanning units 14A and 14B are formed on the TFTsubstrate 21 using a TFT element. The drive electrode scanning units 14Aand 14B are supplied with the display drive voltage VcomDC from thedrive signal generating unit via display wirings LDC and are alsosupplied with the drive signal VcomAC via touch wirings LAC. Thedrive-electrode scanning units 14A and 14B occupy a fixed width Gdv inthe respective frames Gd. The drive-electrode scanning units 14A and 14Bare then configured so as to be capable of driving each of the driveelectrode blocks B arranged in parallel from both sides thereof. Thedisplay wiring LDC for supplying the display drive voltage VcomDC andthe touch wiring LAC for supplying the touch drive signal VcomAC arearranged in parallel to each other in the frames Gd and Gd. The displaywiring LDC is arranged in the side nearer to the display area Ad thanthe touch wiring LAC is. With this structure, the display drive voltageVcomDC supplied through the display wiring LDC stabilizes a potentialstate at edges of the display area Ad. Therefore, the display isstabilized especially in the liquid crystal display unit using liquidcrystal in a horizontal electric field mode.

The display device with a touch detection function 1 illustrated in FIG.7 outputs the touch detection signal Vdet from the short-side side ofthe display unit with a touch detection function 10. Thereby, therouting of wiring in the display device with a touch detection function1 required for connection to the touch IC 110 via the flexible printedwiring board T being a terminal unit is made easy.

The drive-electrode scanning units 14A and 14B may be built into the COG19 instead of being formed in the frames Gd. FIG. 8 is a diagram ofanother example of the module that mounts thereon the display devicewith a touch detection function according to the first embodiment. Inthis example, the drive-electrode scanning units are built in the COG19, and wirings for supplying the display drive voltage VcomDC and thedrive signal VcomAC from the COG 19 to the drive electrode blocks B(drive electrodes COML) are formed.

Booster Circuit

The booster circuit that boosts a power supply voltage Vcc and generatesa power supply voltage Vdd will be explained next. FIG. 9 and FIG. 10are diagrams of examples of the booster circuit. FIG. 9 is a diagram ofthe booster circuit in the sleep mode, and FIG. 10 is a diagram of thebooster circuit in the normal operation mode. A booster circuit 70 isbuilt in the COG 19 as an example, but may be provided outside the COG19.

The booster circuit 70 includes switches 71, 72, 75, and 76, chargepumps 73 and 77, and regulators 74 and 78. In the sleep mode, asillustrated in FIG. 9, the switch 71 is turned off and the switch 72 isturned on. This allows a power supply voltage +Vcc (e.g., about +3V to+5V) supplied from a battery or a main substrate or so of the electronicapparatus to be supplied to the gate driver 100D. Moreover, in the sleepmode, the switch 75 is turned off and the switch 76 is turned on. Thisallows a power supply voltage −Vcc (e.g., about −3V to −5V) suppliedfrom the battery or the main substrate or so of the electronic apparatusto be supplied to the gate driver 100D.

Meanwhile, in the normal operation mode, as illustrated in FIG. 10, theswitch 71 is turned on and the switch 72 is turned off. Thereby, thepower supply voltage +Vcc is supplied to the charge pump 73, and thecharge pump 73 generates a power supply voltage +Vdd (e.g., about +5V to+10V). The power supply voltage +Vdd generated by the charge pump 73 isstabilized by the regulator 74 to be supplied to the gate drivers 12Aand 12B. Moreover, in the normal operation mode, as illustrated in FIG.10, the switch 75 is turned on and the switch 76 is turned off. Thereby,the power supply voltage −Vcc is supplied to the charge pump 77, and thecharge pump 77 generates a power supply voltage −Vdd (e.g., about −5V to−10V). The power supply voltage −Vdd generated by the charge pump 77 isstabilized by the regulator 78 to be supplied to the gate drivers 12Aand 12B.

FIG. 11 and FIG. 12 are diagrams of examples of the charge pump. Thecharge pump 73 includes switches S1 to S3 and capacitors C11 to C12. Inthe charge pump 73, at first, the switch S1 is turned on and one end ofthe capacitor C11 is coupled to the power supply voltage Vcc. The otherend of the capacitor C11 is coupled to a ground potential by the switchS2. The capacitor C11 is thereby charged with electric charges, and aninter-terminal voltage becomes Vcc. The switch S3 is off.

Subsequently, the switch S1 is turned off and the other end of thecapacitor C11 is coupled to a power supply potential Vcc by the switchS2. The switch S3 is then turned on, and the capacitor C11/the powersupply potential Vcc and the capacitor C12 are coupled in parallel toeach other. At this time, an inter-terminal voltage of the capacitor C12is 2×Vcc obtained by adding the supply potential Vcc and theinter-terminal voltage of the capacitor C11, i.e., Vcc. The charge pump73 periodically turns on and off the switches S1 to S3, and therebyenables to boost the power supply voltage Vcc.

The charge pump 73 has been explained so far, and the charge pump 77 hasthe same configuration as that of the charge pump 73.

Display Unit with Touch Detection Function

A configuration example of the display unit with a touch detectionfunction 10 will be explained in detail next. FIG. 13 is across-sectional view of a schematic cross-sectional structure of thedisplay unit with a touch detection function according to the firstembodiment. FIG. 14 is a diagram of an example of a control device forthe display device with a touch detection function according to thefirst embodiment. FIG. 15 is a circuit diagram of a pixel array of thedisplay unit with a touch detection function according to the firstembodiment.

As illustrated in FIG. 13, the display unit with a touch detectionfunction 10 includes the pixel substrate 2, a counter substrate 3arranged opposite to the pixel substrate 2 in a direction perpendicularto the surface of the pixel substrate 2, and a liquid crystal layer 6inserted between the pixel substrate 2 and the counter substrate 3.

The liquid crystal layer 6 modulates light passing therethroughaccording to the state of the electric field, and uses a liquid crystalunit using a liquid crystal in the horizontal electric field mode suchas fringe field switching (FFS) or in-plane switching (IPS). Anorientation film may be provided between the liquid crystal layer 6 andthe pixel substrate 2 and between the liquid crystal layer 6 and thecounter substrate 3 illustrated in FIG. 13.

The counter substrate 3 includes a glass substrate 31 and a color filter32 formed on one face of the glass substrate 31. The touch detectionelectrodes TDL being detection electrodes of the touch detecting unit 30are formed on the other face of the glass substrate 31, and a polarizer35 is disposed on the touch detection electrodes TDL.

The pixel substrate 2 includes the TFT substrate 21 as a circuit board,a plurality of pixel electrodes 22 arranged in a matrix over the TFTsubstrate 21, a plurality of drive electrodes COML formed between theTFT substrate 21 and the pixel electrodes 22, and an insulating layer 24for insulating the pixel electrodes 22 from the drive electrodes COML.

System Configuration Example of Display Device

The pixel substrate 2 includes the display area Ad, the COG 19 havingfunctions of an interface (I/F) and a timing generator, the first gatedriver 12A, the second gate driver 12B, the gate driver 100D, and thesource driver 13, which are provided over the TFT substrate 21. Theflexible printed wiring board T illustrated in FIG. 7 transmits anexternal signal for the COG 19 illustrated in FIG. 14, which is disposedas the COG 19 in FIG. 7, or drive power for driving the COG 19 thereto.The pixel substrate 2 includes the display area Ad which is provided onthe surface of the TFT substrate 21 of a translucent insulatingsubstrate (e.g. a glass substrate) and on which a number of pixelsincluding liquid crystal cells are arranged in a matrix (in the form ofrows and columns), the source driver (horizontal drive circuit) 13, andthe gate drivers (vertical drive circuits) 12A, 12B, and 100D. The gatedrivers (vertical drive circuits) 12A and 12B are arranged across thedisplay area Ad, as the first gate driver 12A and the second gate driver12B.

The display area Ad has a matrix (rows and columns form) structure inwhich the sub-pixels SPix including the liquid crystal layer arearranged in m rows×n columns. In this specification, the row indicates apixel row having n pieces of sub-pixels SPix arrayed in one direction.The column indicates a pixel column having m pieces of sub-pixels SPixarrayed in a direction perpendicular to the direction in which the rowsare arrayed. The values of m and n are determined according to avertical display resolution and a horizontal display resolutionrespectively. In the display area Ad, each of scan lines GCL_(m+1),GCL_(m+2), GCL_(m+3) . . . is wired in each row with respect to anm-row/n-column array of the pixels VPix, and each of signal linesSGL_(n+1), SGL_(n+2), SGL_(n+3), SGL_(n+4), SGL_(n+5) . . . is wired ineach column. In the embodiment, “scan line GCL” may be hereinafterdescribed as a representative of the scan lines GCL_(m+1), GCL_(m+2),GCL_(m+3) . . . , and “signal line SGL” may be hereinafter described asa representative of the signal lines SGL_(n+1), SGL_(n+2), SGL_(n+3),SGL_(n+4), SGL_(n+5) . . . .

A master clock, a horizontal synchronization signal, and a verticalsynchronization signal, which are external signals input from anexternal device, are input to the pixel substrate 2 and supplied to theCOG 19. The COG 19 performs level conversion (boosting) of the masterclock, the horizontal synchronization signal, and the verticalsynchronization signal, each of which has a voltage magnitude of anexternal power supply, to a voltage magnitude of an internal powersupply required for driving the liquid crystal, passes thelevel-converted master clock, horizontal synchronization signal, andvertical synchronization signal through the timing generator, andgenerates a vertical start pulse VST, a vertical clock pulse VCK, ahorizontal start pulse HST, and a horizontal clock pulse HCK. The COG 19supplies the vertical start pulse VST and the vertical clock pulse VCKto the first gate driver 12A, the second gate driver 12B, and the gatedriver 100D, and also supplies the horizontal start pulse HST and thehorizontal clock pulse HCK to the source driver 13. The COG 19 generatesdisplay drive voltage (counter electrode potential) VCOM, which iscalled common potential commonly supplied to the pixels, for the pixelelectrode for each sub-pixel SPix, and supplies the generated commonpotential to the drive electrodes COML.

The first gate driver 12A, the second gate driver 12B, and the gatedriver 100D include a shift register, explained later, and may furtherinclude a latch circuit and the like. The first gate driver 12A, thesecond gate driver 12B, and the gate driver 100D are supplied with thevertical start pulse VST, and the latch circuits thereby sequentiallysample and latch the display data output from the COG 19 insynchronization with the vertical clock pulse VCK in one horizontalperiod. The first gate driver 12A, the second gate driver 12B, and thegate driver 100D sequentially output the digital data for one linelatched in the latch circuits as a vertical scan pulse, and supply thedigital data to the scan lines GCL, to thereby sequentially selectsub-pixels SPix row by row. The first gate driver 12A and the secondgate driver 12B are arranged so as to sandwich the scan lines GCLtherebetween in the extending direction of the scan lines GCL. The gatedriver 100D is arranged adjacent to the second gate driver 12B. Thefirst gate driver 12A, the second gate driver 12B, and the gate driver100D perform output in the order from an upper side of the display areaAd, i.e., from an upper direction of vertical scanning to a lower sideof the display area Ad, i.e., to a lower direction of the verticalscanning.

The source driver 13 is supplied with, for example, 6-bit R (red), G(green), and B (blue) image signals Vsig. The source driver 13 writesdisplay data to sub-pixels SPix of a row selected through verticalscanning performed by the first gate driver 12A and the second gatedriver 12B for each pixel, or for each pixels, or for all pixels at onetime via the signal lines SGL.

Formed on the TFT substrate 21 are thin film transistor (TFT) elementsTr of the sub-pixels SPix illustrated in FIG. 14 and FIG. 15 and wiringssuch as the pixel signal lines SGL for supplying a pixel signal Vpix tothe pixel electrodes 22 illustrated in FIG. 13 and the scan lines GCLfor driving the TFT elements Tr respectively. In this way, the pixelsignal lines SGL are extended in a plane parallel to the surface of theTFT substrate 21, to supply the pixel signal Vpix for displaying animage to the pixels. The liquid crystal display unit 20 illustrated inFIG. 15 has the sub-pixels SPix arrayed in a matrix. The sub-pixel SPixincludes a TFT element Tr and a liquid crystal element LC. The TFTelement Tr includes a thin film transistor, which is an n-channel metaloxide semiconductor (MOS) TFT in this example. A source of the TFTelement Tr is coupled to the pixel signal line SGL, a gate thereof iscoupled to the scan line GCL, and a drain thereof is coupled to one endof the liquid crystal element LC. The liquid crystal element LC iscoupled at one end to the drain of the TFT element Tr, and is coupled atthe other end to the drive electrode COML.

The first gate driver 12A, the second gate driver 12B, and the gatedriver 100D illustrated in FIG. 14 apply a vertical scan pulse to thegates of the TFT elements Tr of the sub-pixels SPix through the scanlines GCL illustrated in FIG. 15 to thereby sequentially select one row(one horizontal line), as a target to be driven, from among thesub-pixels SPix formed in the matrix in the display area Ad. The sourcedriver 13 supplies the pixel signal Vpix to each of the sub-pixels SPixincluding one horizontal line sequentially selected by the first gatedriver 12A, the second gate driver 12B, and the gate driver 100D throughthe respective pixel signal lines SGL. In the sub-pixels SPix, displayof one horizontal line is performed according to the supplied pixelsignal. The drive electrode driver 14 applies the drive signal fordisplay (display drive voltage VcomDC) so as to drive the driveelectrodes COML.

As explained above, the display device with a touch detection function 1drives the first gate driver 12A, the second gate driver 12B, and thegate driver 100D so as to sequentially scan the scan lines GCL_(m+1),GCL_(m+2), and GCL_(m+3) to thereby sequentially select one horizontalline. The display device with a touch detection function 1 causes thesource driver 13 to supply a pixel signal to the pixel Pix belonging tothe one horizontal line, and thereby performs display of the horizontalline one line by one line. When performing the display operation, thedrive electrode driver 14 applies the drive signal Vcom to the driveelectrodes COML corresponding to the selected one horizontal line.

The color filter 32 illustrated in FIG. 13 is structured to periodicallyarray color areas of the color filter colored in three colors, forexample, red (R), green (G), and blue (B), and to associate color areas32R, 32G, and 32B (see FIG. 15) of the three colors of R, G, and B,which are made a set as a pixel Pix, with the sub-pixels SPixillustrated in FIG. 15. The color filter 32 faces the liquid crystallayer 6 in the direction perpendicular to the TFT substrate 21. Thecolor filter 32 may be a combination of other colors if the color areasare colored in different colors.

The sub-pixel SPix illustrated in FIG. 15 is coupled to the othersub-pixels SPix belonging to the same row of the liquid crystal displayunit 20 through the scan line GCL. The scan lines GCL are coupled to thegate drivers 12 and 100D and are supplied with a scan signal Vscan fromthe gate drivers 12 and 100D. The sub-pixel SPix is coupled to the othersub-pixels SPix belonging to the same column of the liquid crystaldisplay unit 20 through the pixel signal line SGL. The pixel signallines SGL are coupled to the source driver 13 and are supplied with thepixel signal Vpix from the source driver 13.

FIG. 16 is a schematic diagram for explaining a relation between thesource driver and the pixel signal lines in the module that mountsthereon the display device with a touch detection function according tothe first embodiment. As illustrated in FIG. 16, the display device witha touch detection function 1 is configured so that the pixel signallines SGL are coupled to the source driver 13 built in the COG 19 viathe source selector 13S. The source selector 13S performs a switchingoperation according to each of switch control signals Vsel.

As illustrated in FIG. 16, the source driver 13 generates and outputs apixel signal Vpix based on the image signal Vsig and a source drivercontrol signal supplied from the control unit 11. The source driver 13generates a pixel signal, in which the pixel signal Vpix of sub-pixelsSPix (three in this example) in the liquid crystal display unit 20 ofthe display unit with a touch detection function 10 is time-divisionmultiplexed, from the image signal Vsig for one horizontal line, andsupplies the generated pixel signal to the source selector 13S. Thesource driver 13 also generates switch control signals Vsel (VselR,VselG, and VselB) required for separating the pixel signal Vpixmultiplexed on the image signal Vsig therefrom and supplies the imagesignal Vsig and the switch control signals Vsel to the source selector13S. The multiplexing allows the number of wirings between the sourcedriver 13 and the source selector 13S to be decreased.

The source selector 13S separates the pixel signals Vpix time-divisionmultiplexed on the image signal Vsig based on the image signal Vsig andthe switch control signal Vsel supplied from the source driver 13, andsupplies the separated pixel signals Vpix to the liquid crystal displayunit 20 of the display unit with a touch detection function 10.

The source selector 13S includes, for example, three switches SWR, SWG,and SWB, and one ends of the three switches SWR, SWG, and SWB arecoupled to each other and are supplied with the image signal Vsig fromthe source driver 13. The other ends of the switches SWR, SWG, and SWBare coupled to the sub-pixels SPix via the pixel signal lines SGLrespectively in the liquid crystal display unit 20 of the display unitwith a touch detection function 10. The three switches SWR, SWG, and SWBare controlled so as to be switched by the switch control signals Vsel(VselR, VselG, and VselB), respectively, supplied from the source driver13. This configuration enables the source selector 13S totime-divisionally and sequentially switch the switches SWR, SWG, and SWBaccording to the switch control signal Vsel to be changed to the ONstate. Thus, the source selector 13S separates the pixel signals Vpix(VpixR, VpixG, and VpixB) from the multiplexed image signal Vsig. Thesource selector 13S then supplies the pixel signals Vpix to the threesub-pixels SPix respectively. The color areas 32R, 32G, and 32B coloredin the three colors: red (R), green (G), and blue (B) are associatedwith the sub-pixels SPix respectively. Therefore, the pixel signal VpixRis supplied to the sub-pixel SPix corresponding to the color area 32R.The pixel signal VpixG is supplied to the sub-pixel SPix correspondingto the color area 32G. The pixel signal VpixB is supplied to thesub-pixel SPix corresponding to the color area 32B.

A sub-pixel SPix is coupled to the other sub-pixels SPix belonging tothe same row of the liquid crystal display unit 20 by the driveelectrode COML. The drive electrode COML is coupled to the driveelectrode driver 14 and is supplied with the display drive voltageVcomDC from the drive electrode driver 14. In other words, in thisexample, the sub-pixels SPix belonging to the same row share the driveelectrode COML.

The gate drivers 12 and 100D illustrated in FIG. 1 apply the scan signalVscan to the gates of the TFT elements Tr in the sub-pixels SPix throughthe scan line GCL illustrated in FIG. 15 to thereby sequentially selectone row (one horizontal line), as a target to be driven, from among thesub-pixels SPix formed in the matrix in the liquid crystal display unit20. The source driver 13 illustrated in FIG. 1 supplies the pixelsignals Vpix to the sub-pixels SPix forming one horizontal linesequentially selected by the gate driver 12 through the respective pixelsignal lines SGL illustrated in FIG. 15. In the sub-pixels SPix, displayof one horizontal line is performed according to the supplied pixelsignals Vpix. The drive electrode driver 14 illustrated in FIG. 1applies the drive signal Vcom to the drive electrodes COML so as todrive the drive electrodes COML for each drive electrode block Bincluding a predetermined number of drive electrodes COML as illustratedin FIG. 7 and FIG. 15.

As explained above, the liquid crystal display unit 20 drives the gatedrivers 12 and 100D so as to time-divisionally and sequentially scan thescan lines GCL to thereby sequentially select one horizontal line. Inthe liquid crystal display unit 20, the source driver 13 supplies thepixel signals Vpix to the sub-pixels SPix belonging to the onehorizontal line, to thereby perform display of the horizontal line oneline by one line. When performing the display operation, the driveelectrode driver 14 applies the display drive voltage VcomDC to thedrive electrode block including the drive electrode COML correspondingto the one horizontal line.

The drive electrode COML according to the present embodiment functionsas a drive electrode of the liquid crystal display unit 20 and alsofunctions as a drive electrode of the touch detecting unit 30. FIG. 17is a perspective view of a configuration example of drive electrodes andtouch detection electrodes of the display unit with a touch detectionfunction according to the first embodiment. The drive electrodes COMLillustrated in FIG. 17 face the pixel electrodes 22 in the directionperpendicular to the surface of the TFT substrate 21 as illustrated inFIG. 13. The touch detecting unit 30 includes the drive electrodes COMLprovided on the pixel substrate 2 and the touch detection electrodes TDLprovided on the counter substrate 3. The touch detection electrodes TDLare formed from stripe-shaped electrode patterns extending along adirection intersecting an extending direction of the electrode patternsof the drive electrode COML. The touch detection electrodes TDL face thedrive electrodes COML in the direction perpendicular to the surface ofthe TFT substrate 21. Each electrode pattern of the touch detectionelectrodes TDL is coupled to an input of the amplifier 42 of the touchdetection unit 40 and to an input of the touch-detection controller 100.The electrode pattern in which the drive electrode COML and the touchdetection electrode TDL intersect each other produces a capacitance atthe intersection. The touch detection electrode TDL or the driveelectrode COML (drive electrode block) is not limited to the shape inwhich it is divided into a plurality of stripes. For example, the touchdetection electrode TDL or the drive electrode COML (drive electrodeblock) may be comb-shaped. Alternatively, the touch detection electrodeTDL or the drive electrode COML (drive electrode block) has only to bedivided into portions, and therefore the shape of each slit that dividesthe drive electrode COML may be a straight line or a curve line.

With this structure, in the touch detecting unit 30, the drive electrodedriver 14 drives so as to time-divisionally and line-sequentially scanthe drive electrode block B illustrated in FIG. 7 when performing touchdetection operation. The drive electrode block B (one detection block)of the drive electrodes COML is thereby sequentially selected in a scandirection Scan. The touch detecting unit 30 then outputs the touchdetection signal Vdet from each of the touch detection electrodes TDL.In this way, the touch detecting unit 30 is configured so as to performthe touch detection on the one detection block.

FIG. 18, FIG. 19, and FIG. 20 are schematic diagrams of an operationexample of touch detection in the display device with a touch detectionfunction according to the first embodiment. A supply operation of thedrive signal VcomAC to each of partial detection regions RT1 to RT10 inthe case in which a touch detection surface is formed with 10 partialdetection regions RT1 to RT10 is illustrated in FIG. 18 to FIG. 20. Eachof partial detection regions RT is set to a width (e.g., about 5 mm)corresponding to the size of a finger of the user operating it. Thedrive electrode driver 14 applies the drive signal VcomAC to the driveelectrodes COML in each partial detection region RT. A shaded portionindicates the partial detection region RT supplied with the drive signalVcomAC, and the display drive voltage VcomDC is supplied to the otherpartial detection regions RT. The drive electrode driver 14 illustratedin FIG. 1 selects the partial detection region RT3 from among thepartial detection regions RT as targets for touch detection operationillustrated in FIG. 18, and applies the touch drive signal VcomACthereto. Subsequently, the drive electrode driver 14 selects the partialdetection region RT4 from among the partial detection regions RTillustrated in FIG. 19, and applies the touch drive signal VcomACthereto. The drive electrode driver 14 then selects the partialdetection region RT5 from among the partial detection regions RTillustrated in FIG. 20, and applies the touch drive signal VcomACthereto. In this way, the drive electrode driver 14 sequentially selectseach of the partial detection regions RT and applies the touch drivesignal VcomAC to the drive electrodes COML belonging to the selectedpartial detection region RT, to thereby scan all the partial detectionregions RT. In this example, the number of partial detection regions RTis set to 10 for the sake of simplicity of explanation; however, theembodiment is not limited thereto. In addition, one partial detectionregion RT may include one drive electrode block B, or one partialdetection region RT may include a plurality of drive electrode blocks B.

In the touch detecting unit 30, the drive electrode block B belonging tothe partial detection region RT illustrated in FIG. 18 to FIG. 20corresponds to the drive electrode E1 in the basic principle of thecapacitive touch detection. One of the touch detection electrodes TDL inthe touch detecting unit 30 corresponds to the touch detection electrodeE2. The touch detecting unit 30 is configured to detect a touchaccording to the basic principle. As illustrated in FIG. 17, mutuallythree-dimensional intersecting electrode patterns forms capacitive-typetouch sensors in a matrix. Therefore, by scanning over the entire touchdetection surface of the touch detecting unit 30, a position where anexternal proximity object comes in contact with or is in proximity tothe touch detection surface can be detected.

Drive Signal Generating Unit and Drive Electrode Driver

FIG. 21 is a block diagram of the drive signal generating unit of thedrive electrode driver according to the first embodiment. A drive signalgenerating unit 14Q includes a high-level voltage generator 61, alow-level voltage generator 62, buffers 63, 64, and 66, and a switchingcircuit 65.

The high-level voltage generator 61 generates a high-level voltage ofthe touch drive signal VcomAC. The low-level voltage generator 62generates a direct-current voltage of the display drive voltage VcomDC.The voltage generated by the low-level voltage generator 62 is used alsoas a low-level voltage of the touch drive signal VcomAC. The buffer 63outputs the voltage supplied from the high-level voltage generator 61while performing an impedance conversion, and supplies the voltage tothe switching circuit 65. The buffer 64 outputs the voltage suppliedfrom the low-level voltage generator 62 while performing an impedanceconversion, and supplies the voltage to the switching circuit 65. Theswitching circuit 65 alternately repeats a case when a drive controlsignal EXVCOM is at a high level and a case when the drive controlsignal EXVCOM is at a low level based on the drive control signal EXVCOMto generate a touch drive signal VcomAC. The switching circuit 65outputs the voltage supplied from the buffer 63 when the drive controlsignal EXVCOM is at the high level, and outputs the voltage suppliedfrom the buffer 64 when the drive control signal EXVCOM is at the lowlevel. When the drive control signal EXVCOM is at the low level, theswitching circuit 65 outputs the voltage supplied from the buffer 64 asa direct-current voltage of the display drive voltage VcomDC based onthe drive control signal EXVCOM. The buffers 63 and 64 are formed of,for example, a voltage follower. The voltage output from switchingcircuit 65 is output to an output terminal 65E. The buffer 66 outputsthe voltage supplied from the low-level voltage generator 62 whileperforming an impedance conversion, and supplies the direct-currentvoltage of the display drive voltage VcomDC to an output terminal 66E.

FIG. 22 is a block diagram of the drive electrode driver according tothe first embodiment. The drive-electrode scanning units 14A and 14Binclude a scanning control unit 51, a touch detection scanning unit 52,and a drive unit 530. The drive unit 530 includes drive units 53(k) to53(k+3) having the same number as that of the drive electrode blocks B.The scanning control unit 51 is mounted on the COG 19. The touchdetection scanning unit 52 and the drive unit 530 are arranged in theframe Gd provided around the display area Ad. Hereinafter, when any oneof the drive units 53(k) to 53(k+3) is indicated, just a drive unit 53is used.

The scanning control unit 51 supplies a control signal SDCK and a scanstart signal SDST to the touch detection scanning unit 52 based on thecontrol signal supplied from the control unit 11. The display wiring LDCis supplied with the display drive voltage VcomDC output from the drivesignal generating unit 14Q via the output terminal 66E. The touch wiringLAC is supplied with the touch drive signal VcomAC output from the drivesignal generating unit 14Q via the output terminal 65E. The scanningcontrol unit 51 supplies a drive electrode selection signal VCOMSELsupplied with the touch drive signal VcomAC from the drive signalgenerating unit 14Q to the drive unit 530.

The touch detection scanning unit 52 includes shift registers 52SR fordrive electrodes, and generates scan signals ST(k), ST(k+1), ST(k+2),ST(k+3) . . . in order to select a drive electrode COML to be appliedwith the touch drive signal VcomAC. Specifically, in the touch detectionscanning unit 52, triggered by the scan start signal SDST supplied fromthe scanning control unit 51 and synchronized with the control signalSDCK, the shift register 52SR is sequentially transferred at eachtransfer stage of the shift registers 52SR, and the shift registers aresequentially selected. The selected shift register 52SR transmitscorresponding one of the scan signals ST(k), ST(k+1), ST(k+2), ST(k+3) .. . to corresponding one of AND circuits 54 of the drive unit 530. Whenthe selected shift register 52SR supplies, for example, a high-levelsignal as a k+2th scan signal ST(k+2) to a k+2th drive unit 53(k+2), thetouch detection scanning unit 52 is configured so that the drive unit53(k+2) applies the drive signal VcomAC to the drive electrodes COMLbelonging to a k+2th drive electrode block B(k+2). Hereinafter, when anyone of the scan signals ST(k), ST(k+1), ST(k+2), ST(k+3) . . . isindicated, a scan signal ST may be used.

The drive unit 530 is a circuit that applies the display drive voltageVcomDC or the touch drive signal VcomAC supplied from the drive signalgenerating unit 14Q to the drive electrode COML based on the scan signalST supplied from the touch detection scanning unit 52 and the driveelectrode selection signal VCOMSEL supplied from the scanning controlunit 51. The drive unit 53 is provided corresponding to each outputsignal of the touch detection scanning unit 52, and applies the drivesignal Vcom to a corresponding drive electrode block B.

The drive unit 53 includes the AND circuit 54 and one selection switchSW1 (SW2, SW3, SW4) for each drive electrode block B. The AND circuit 54generates and outputs a logical product (AND) of the scan signal STsupplied from the touch detection scanning unit 52 and the driveelectrode selection signal VCOMSEL supplied from the scanning controlunit 51. The AND circuit 54 has a buffer function of amplifyingoperation of the selection switch SW1 (SW2, SW3, SW4) to an amplitudelevel at which the operation can be controlled. The operation of theselection switch SW1 is controlled based on the signal supplied from theAND circuit 54. One end of the selection switch SW1 is coupled to thedrive electrodes COML included in the drive electrode block B and theother end of the selection switch SW1 is coupled to either one of thedisplay wiring LDC and the touch wiring LAC.

With this structure, when the scan signal ST is at a high level and thedrive electrode selection signal VCOMSEL is at a high level, the driveunit 53 outputs the touch drive signal VcomAC as the drive signal Vcom.When the scan signal ST is at a low level or the drive electrodeselection signal VCOMSEL is at a low level, the drive unit 53 separatesthe drive electrode block B from the touch wiring LAC and couples thedrive electrode block B to the display wiring LDC. The drive electrodeblock B selected as an output destination of the touch drive signalVcomAC is a selected drive electrode block STX. The drive electrodeblock B not selected as an output destination of the touch drive signalVcomAC is a non-selected drive electrode block NTX. For example, thedrive unit 53(k+2) illustrated in FIG. 22 applies the drive signalVcomAC to the drive electrodes COML belonging to the k+2th driveelectrode block B(k+2), and therefore the selected drive electrode blockSTX is the drive electrode block B(k+2). Drive electrode blocks B(k),B(k+1), and B(k+3) which are not selected as output destinations of thedrive signal VcomAC are non-selected drive electrode blocks NTX.

When the liquid crystal display unit 20 is performing display operation,the scan signal ST is at the low level, and the drive unit 53 couplesone selection switch SW1 (SW2, SW3, SW4) to the display wiring LDC foreach drive electrode block B, and outputs the display drive voltageVcomDC as the drive signal Vcom.

FIG. 23 is a block diagram of a drive unit of the drive electrode driveraccording to the first embodiment. FIG. 24 is a block diagram of anarrangement example of selection switches of the drive electrode driveraccording to the first embodiment. FIG. 23 and FIG. 24 describe aconfiguration of the first gate driver 12A; however, the second gatedriver 12B and the gate driver 100D have the similar configuration. Inthe following, although the selection switch SW1 will be explained as atypical one, the selection switches SW2, SW3, and SW4 have the similarconfiguration. The first gate driver 12A includes gate shift registers120SR. The gate shift registers 120SR start operation in response to thevertical start pulse VST to be sequentially selected in the verticalscanning direction in synchronization with the vertical clock VCK, andthe selected gate shift register 120SR outputs a vertical selectionpulse to a corresponding one of the scan lines GCL via the buffercircuit.

The selection switch SW1 includes a plurality of switches COMSW whichare provided for each drive electrode COML. All the switches COMSWoperate for each drive electrode COML according to switch controlsignals Ssw and Sxsw. All the switches COMSW operate for each driveelectrode COML, and thereby time-divisionally select either one ofcoupling between the touch wiring LAC and the drive electrode COML andcoupling between the display wiring LDC and the drive electrode COML.

When the switch COMSW has, for example, a CMOS switch CMOS1 and a CMOSswitch CMOS2 which are formed as a unit of circuit, a plurality of unitsof circuits are provided for each drive electrode COML. Each of the CMOSswitch CMOS1 and the CMOS switch CMOS2 includes a transistor NMOS havingan N-channel gate and a transistor PMOS having a P-channel gate.

In the CMOS switch CMOS1, a switch signal line GSW is coupled to gatesof the transistor NMOS and the transistor PMOS. In the CMOS switchCMOS2, a switch signal line GxSW is coupled to gates of the transistorNMOS and the transistor PMOS. A switch control signal Ssw supplied tothe switch signal line GSW and a switch control signal Sxsw supplied tothe switch signal line GxSW are signals between which the high level andthe low level of potential are inverted each other. Therefore, the CMOSswitch CMOS1 and the CMOS switch CMOS2 are synchronize with either oneof coupling between the touch wiring LAC and the drive electrode COMLand coupling between the display wiring LDC and the drive electrodeCOML, and can thereby perform the same selection. In this way, theselection switch SW1 includes the switches COMSW for each driveelectrode COML, and the switches COMSW are coupled in parallel to eachother between the touch wiring LAC and the drive electrode COML. All theswitches COMSW operate for each drive electrode COML according to theswitch control signal Ssw or Sxsw being the selection signal, couple thetouch wiring LAC to the drive electrode COML, and apply the touch drivesignal VcomAC.

The AND circuit 54 includes an inverter 541, a switching circuit 542, abuffer 543, and an inverter 544. The inverter 541 outputs an invertedlogic of an output signal from a transfer stage selected of the shiftregisters 52SR for drive electrode, when the scan signal ST is at thehigh level, to the switching circuit 542. The switching circuit 542switches the an input and an output of the inverter 541 according to thedrive electrode selection signal VCOMSEL to output the switch controlsignal Ssw to the buffer 543. The buffer 543 amplifies the switchcontrol signal Ssw, and supplies the amplified signal to the switchsignal line GSW. The inverter 544 generates an inverted logic of theswitch control signal Ssw output by the buffer 543, outputs the invertedlogic as the switch control signal Sxsw, and supplies the switch controlsignal Sxsw to the switch signal line GxSW.

The CMOS switches CMOS1 and CMOS2 are coupled to the touch wiring LAC byrespective coupling conductors Q3. The CMOS switches CMOS1 and CMOS2 arecoupled to the display wiring LDC by respective coupling conductors Q2.The CMOS switches CMOS1 and CMOS2 are coupled to the drive electrodesCOML by respective coupling conductors Q1. The switch control signal Sswor Sxsw is input to the gates of the transistors NMOS and thetransistors PMOS, which enables the CMOS switches CMOS1 and CMOS2 toselect either one of coupling between the coupling conductor Q1 and thecoupling conductor Q2 and coupling between the coupling conductor Q3 andthe coupling conductor Q1.

As illustrated in FIG. 24, the scan line GCL is wired in the same layeras that of the switch signal lines GSW and GxSW. The scan line GCL is agate line of the transistor in the same manner as that of the switchsignal lines GSW and GxSW, and is formed in the same process, so thatthe manufacturing process can be reduced. The scan line GCLthree-dimensionally intersects the touch wiring LAC and the displaywiring LDC via the insulating layer. The selection switch SW1 isdisposed in an area between scan lines GCL (e.g., between the scan lineGCL_(m+1) and the scan line GCL_(m+2)) that three-dimensionallyintersect the touch wiring LAC (display wiring LDC). A distance betweenthe scan lines GCL that three-dimensionally intersect the touch wiringLAC (display wiring LDC) is the same as a distance between adjacent scanlines GCL in the display area Ad.

Basic Principle of Self-Capacitance Type Touch Detection

The touch-detection controller 100 operates in the sleep mode based onthe basic principle of the self-capacitance type touch detection todetect the presence or absence of a touch. The basic principle of theself-capacitance type touch detection in the display device with a touchdetection function 1 will be explained below with reference to FIG. 25to FIG. 31. FIG. 25 and FIG. 26 are explanatory diagrams for explainingthe basic principle of the self-capacitance type touch detection andillustrating a state where a finger is not in contact with or inproximity to the device. FIG. 27 and FIG. 28 are explanatory diagramsfor explaining the basic principle of the self-capacitance type touchdetection and illustrating a state where a finger is not in contact withor in proximity to the device. FIG. 29 is an explanatory diagramillustrating a detection circuit. FIG. 30 is an explanatory diagramillustrating an equivalent circuit of the detection circuit in FIG. 29.FIG. 31 is a diagram of an example of waveforms of the detection circuitin FIG. 29.

First of all, as illustrated in FIG. 25, the touch detection electrodeTDL is coupled to the power supply voltage Vcc by a switch 201. Thetouch detection electrode TDL has a capacitance C3, and electric chargeflows from the power supply voltage Vcc to the touch detection electrodeTDL in a direction of arrow 203, and the touch detection electrode TDLis charged with electric charge according to the capacitance C3.

Subsequently, as illustrated in FIG. 26, the touch detection electrodeTDL is coupled to a detection circuit 202 by the switch 201, and theelectric charge charged to the touch detection electrode TDL flows tothe detection circuit 202 in a direction of arrow 204. The detectioncircuit 202 measures the electric charge flowed from the touch detectionelectrode TDL to thereby enable detection of the capacitance C3 in thetouch detection electrode TDL.

A case in which the finger is in contact with or in proximity to thetouch detection electrode TDL will be explained next. As illustrated inFIG. 27, when the finger comes in contact with or in proximity to thetouch detection electrode TDL, the capacitance C2 of the finger is addedto the capacitance C3 of the touch detection electrode TDL. Therefore,when the touch detection electrode TDL is coupled to the power supplyvoltage Vcc by the switch 201, the electric charge flows from the powersupply voltage Vcc to the touch detection electrode TDL in the directionof the arrow 203, and the touch detection electrode TDL and the fingerare charged with electric charge according to the capacitances C3 andC2.

Subsequently, as illustrated in FIG. 28, the touch detection electrodeTDL is coupled to the detection circuit 202 by the switch 201, and theelectric charge charged to the touch detection electrode TDL and thefinger flows to the detection circuit 202 in the direction of the arrow204. The detection circuit 202 measures the electric charge flowed fromthe touch detection electrode TDL and the finger to thereby enabledetection of the capacitances of the touch detection electrode TDL andthe finger.

FIG. 29 is an explanatory diagram illustrating the detection circuit. Ameasurement procedure of a capacitance Cx of the touch detectionelectrode TDL will be explained below with reference to FIG. 29.

Step 1: First of all, a switch 207 is tuned on and switches 206 and 208are tuned off, a series circuit of a resistor Rc and a capacitor Cc iscoupled to a point between the power supply voltage Vcc and a groundpotential, and electric charge is charged to the capacitor Cc.

Step 2: Then, all the switches 206 to 208 are switched off. The electriccharge of the capacitor Cc is maintained.

Step 3: The switches 206 and 208 are on for a given period of time, anda coupling point between a capacitor Cx and a capacitor Cr and acoupling point between the capacitor Cr and the resistor Rc aregrounded. The electric charge of the capacitor Cc is partiallydischarged via the resistor Rc while all the electric charge of thecapacitors Cx and Cr are discharged.

Step 4: All the switches 206 to 208 are switched off. The electriccharge of the capacitor Cc is moved to the capacitors Cx and Cr.

Step 5: A comparator 205 compares an inter-terminal voltage Vx of thecapacitor Cx with a reference voltage Vref. As illustrated in FIG. 30,an inter-terminal voltage Vc of the capacitor Cc at this time is a sumof an inter-terminal voltage Vr of the capacitor Cr and theinter-terminal voltage Vx of the capacitor Cx.

Respective relationships between the voltages Vc, Vr, and Vx andcapacitances Cc, Cr, and Cx can be expressed in the following equations.

Vc=Vr+Vx  (1)

Vr:Vx=1/Cr:1/Cx  (2)

Vx=Cr/(Cr+Cx)xVc  (3)

The steps 3 to 5 are repeatedly executed until Vx<Vref. As illustratedin the equation (3), when the finger comes in contact with or inproximity to the touch detection electrode TDL and the capacitance Cx isthereby increased, the number of discharge cycles (number of repeats)until the condition Vx<Vref is satisfied is reduced. Touch/non-touch ofthe finger can be determined by the number of discharge cycles.

In FIG. 31, a time period t20 is a time period during which the fingeris not in contact with or in proximity to the touch detection electrodeTDL, and a time period t21 is a time period during which the finger isin contact with or in proximity to the touch detection electrode TDL.Moreover, in FIG. 31, a bar graph indicates the voltage Vx and a linegraph indicates the voltage Vc.

The voltage Vc gradually lowers in association with repetition of thesteps 3 to 5. The voltage Vx is expressed by the equation (3).

When the finger comes in contact with or in proximity to the touchdetection electrode TDL and the capacitance Cx is thereby increased, thenumber of discharge cycles (number of repeats) to reach Vx<Vref isreduced.

When the finger is not in contact with or in proximity to the touchdetection electrode TDL, the number of discharge cycles (number ofrepeats) in a time period t41 from a measurement start time t31 to atime t32 at which Vx<Vref is obtained is eight times. Meanwhile, whenthe finger is in contact with or in proximity to the touch detectionelectrode TDL, the number of discharge cycles (number of repeats) in atime period t42 from a measurement start time t33 to a time t34 at whichVx<Vref is obtained is six times.

In this way, the detection circuit 202 counts the number of dischargecycles (number of repeats) up to Vx<Vref, and can thereby determinewhether the finger is in contact with or in proximity to the touchdetection electrode TDL.

Here, the TFT substrate 21 corresponds to a specific example of“substrate” according to the present disclosure. The pixel electrode 22corresponds to a specific example of “pixel electrode” according to thepresent disclosure. The pixel signal line SGL corresponds to a specificexample of “pixel signal line” according to the present disclosure. Thedrive electrode COML corresponds to a specific example of “driveelectrode” according to the present disclosure. The liquid crystalelement LC corresponds to a specific example of “display function layer”according to the present disclosure. The gate drivers 12 and 100D, thesource driver 13, and the drive electrode driver 14 correspond to aspecific example of “control device” according to the presentdisclosure. The touch detection electrode TDL corresponds to “touchdetection electrode” according to the present disclosure. Thetouch-detection controller 100 corresponds to a specific example of“touch-detection controller” according to the present disclosure.

Operation and Action

Operation and action of the display device with a touch detectionfunction 1 according to the first embodiment will be explained below. Inthe following explanation, the drive signal Vcom being a drive signalfor display is described as the display drive voltage VcomDC, and thedrive signal Vcom being a touch drive signal detection is described asthe touch drive signal VcomAC.

Overview of Entire Operation

First of all, an overview of an entire operation of the display devicewith a touch detection function 1 will be explained below with referenceto FIG. 1. The control unit 11 supplies a control signal to the gatedriver 12, the source driver 13, the drive electrode driver 14, and thetouch detection unit 40 based on the video signal Vdisp supplied from anapplication processor (host CPU) and controls so that these unitsoperate in synchronization with one another. The memory 11 a of thecontrol unit 11 writes the video signal Vdisp supplied from theapplication processor in synchronization with a vertical synchronizationsignal Vsync and a horizontal synchronization signal Hsync which arealso supplied from the application processor. The memory 11 a reads thewritten data in synchronization with an internal clock of the displaydevice with a touch detection function 1 at a speed higher than that ofthe write.

The gate driver 12 supplies the scan signal Vscan to the liquid crystaldisplay unit 20 and sequentially selects one horizontal line targetedfor display drive. The source driver 13 generates a pixel signal Vsig inwhich pixel signals Vpix are multiplexed and a corresponding switchcontrol signal Vsel, and supplies the generated signals to the sourceselector 13S. The source selector 13S separates and generates the pixelsignals Vpix based on the pixel signal Vsig and the switch controlsignal Vsel, and supplies each of the pixel signals Vpix to each of thepixels Pix that form one horizontal line. The drive electrode driver 14applies the display drive voltage VcomDC to all the drive electrodesCOML in the display period Pd. The drive electrode driver 14 alsoapplies the touch drive signal detection VcomAC to the drive electrodesCOML belonging to the partial detection region RT targeted for touchdetection operation and applies the display drive voltage VcomDC to theother drive electrodes COML in the touch detection period Pt. Thedisplay unit with a touch detection function 10 performs displayoperation in the display period Pd, also performs touch detectionoperation in the touch detection period Pt, and outputs the touchdetection signal Vdet from the touch detection electrode TDL.

The touch detection unit 40 detects a touch on the touch detectionsurface based on the touch detection signal Vdet. Specifically, theamplifier 42 removes a high frequency component (noise component)contained in the touch detection signal Vdet, extracts a touchcomponent, and outputs the touch component. The A/D convertor 43converts the analog signal output from the amplifier 42 into a digitalsignal. The signal processor 44 detects the presence or absence of atouch performed on the touch detection surface based on the outputsignal of the A/D convertor 43. When the presence of a touch is detectedby the signal processor 44, the coordinate extractor 45 calculates touchpanel coordinates of the touch. The detection-timing controller 46controls so that the amplifier 42, the A/D convertor 43, the signalprocessor 44, and the coordinate extractor 45 operate in synchronizationwith one another.

Detailed Operation

The operation of the display device with a touch detection function 1will be explained in detail below with reference to some of thedrawings.

FIG. 32 is a diagram schematically illustrating operation of the displaydevice with a touch detection function in one frame period (1F). In FIG.32, the horizontal axis represents a time and the vertical axisrepresents a position on the display screen in the vertical direction. Avertical blanking period is omitted in FIG. 32.

FIG. 33 is a timing chart of operation of the display device with atouch detection function, where (A) represents a waveform of thevertical synchronization signal Vsync, (B) represents a waveform of thehorizontal synchronization signal Hsync, (C) represents a partialdisplay region RD in which video information written by memory write WMis displayed, (D) represents a partial display region RD targeted fordisplay drive DD, and (E) represents a partial detection region RTtargeted for touch detection drive DT.

In this example, 10 touch detection periods Pt and 10 display periods Pdare alternately provided in one frame period (1F). In the display panelwith a touch detection function 10, the touch detection drive DT isperformed in the touch detection periods Pt and the display drive DD isperformed in the display periods Pd.

The memory 11 a sequentially writes data of one-tenth of the videoinformation for one frame by each one horizontal line (memory write WM)based on the video signal Vdisp, the vertical synchronization signalVsync, and the horizontal synchronization signal Hsync which aresupplied from the application processor. The memory 11 a thensequentially writes subsequent data for one-tenth thereof by each onehorizontal line while overwriting the previous data for one-tenththereof. The memory 11 a sequentially reads the written data by each onehorizontal line at a speed higher than that of the write before thewritten data is erased by being overwritten. The gate driver 12 and thesource driver 13 then drive the partial display regions RD of the liquidcrystal display unit 20 through line-sequential scanning based on theread data (display drive DD).

In this way, the display device with a touch detection function isconfigured so that the memory 11 a sequentially reads the written databy each one horizontal line at a speed higher than that of the write andthe display drive DD is performed based on the read data. In otherwords, duration of the display period Pd in which the display drive DDis performed is shorter than the time in which the memory 11 a writesthe data of one-tenth of the video information for one frame. Thedisplay device with a touch detection function uses the time (touchdetection period Pt) ensured by making the display period Pd shorter inthis way to perform the touch detection drive DT in each partialdetection region RT.

In this example as illustrated in FIG. 32, for the touch detection driveDT, two partial detection regions RT are sequentially selected as atarget to be driven in each touch detection period Pt. That is, in thisexample, touch detection scanning over the touch detection surface isperformed at a scanning speed twice as high as that of display scanning.In other words, the display device with a touch detection function canperform the touch detection scanning twice while performing the displayscanning once. In this way, the display device with a touch detectionfunction frequently performs the touch detection scanning and canthereby immediately respond to a touch by an external proximity object,thus improving response characteristics to the touch.

Operation in Normal Operation Mode

Operation in the normal operation mode of the display device with atouch detection function 1, i.e., display operation in the displayperiod Pd and touch detection operation in the touch detection period Ptwill be explained next.

FIG. 34 is a timing chart of display operation of the display devicewith a touch detection function, where (A) represents a waveform of thescan signal Vscan, (B) represents a waveform of the image signal Vsig,(C) represents a waveform of the switch control signal Vsel, (D)represents a waveform of the pixel signal Vpix, and (E) represents awaveform of the drive signal Vcom.

The display device with a touch detection function 1 is configured sothat, in the display period Pd, the drive electrode driver 14 appliesthe display drive voltage VcomDC to all the drive electrodes COML ((E)in FIG. 34), and the gate driver 12 sequentially applies the scan signalVscan to the scan line GCL in each one horizontal period (1H) to therebyperform display scanning. Details thereof are explained below.

After the one horizontal period (1H) is started at a timing t1, at atiming t2, the gate driver 12 applies the scan signal Vscan to an n-thscan line GCL (n) related to the display operation, and the scan signalVscan (n) changes from a low level to a high level ((A) in FIG. 34).Thereby the gate driver 12 selects one horizontal line targeted fordisplay operation.

Then, the source driver 13 supplies a pixel voltage VR for a redsub-pixel SPix, as the image signal Vsig, to the source selector 13S((B) in FIG. 34) and generates a switch control signal VselR that ischanged to the high level in a period in which the pixel voltage VR issupplied ((C) in FIG. 34). The source selector 13S turns on a switch SWRin the period in which the switch control signal VselR becomes the highlevel, thereby separates the pixel voltage VR supplied from the sourcedriver 13 from the image signal Vsig, and supplies the separated pixelvoltage VR, as a pixel signal VpixR, to the red sub-pixel SPix via thepixel signal line SGL ((D) in FIG. 34). After the switch SWR becomes offstate, the pixel signal line SGL is changed to a floating state, andtherefore the voltage of the pixel signal line SGL is maintained ((D) inFIG. 34).

Likewise, the source driver 13 supplies a pixel voltage VG for a greensub-pixel SPix together with a corresponding switch control signal VselGto the source selector 13S ((B) and (C) in FIG. 34). The source selector13S separates the pixel voltage VG from the image signal Vsig based onthe switch control signal VselG and supplies the separated pixel voltageVG, as a pixel signal VpixG, to the green sub-pixel SPix via the pixelsignal line SGL ((D) in FIG. 34).

Thereafter, similarly, the source driver 13 supplies a pixel voltage VBfor a blue sub-pixel SPix together with a corresponding switch controlsignal VselB to the source selector 13S ((B) and (C) in FIG. 34). Thesource selector 13S separates the pixel voltage VB from the image signalVsig based on the switch control signal VselB and supplies the separatedpixel voltage VB, as a pixel signal VpixB, to the blue sub-pixel SPixvia the pixel signal line SGL ((D) in FIG. 34).

Subsequently, at a timing t3, the gate driver 12 changes the scan signalVscan (n) of the n-th scan signal line GCL from the high level to thelow level ((A) in FIG. 34). Thereby the sub-pixels SPix in the onehorizontal line related to the display operation are electricallydisconnected from the pixel signal line SGL.

Then, at a timing t4, the one horizontal period (1H) is ended and a newone horizontal period (1H) is started, and display drive is performed ona next line (n+1th line).

From then on, the display device with a touch detection function 1repeats the operation, so that the display operation in the partialdisplay region RD is performed through line-sequential scanning in eachdisplay period Pd.

FIG. 35 is a timing chart of touch detection operation of the displaydevice with a touch detection function, where (A) represents a waveformof the drive signal Vcom, and (B) represents a waveform of the touchdetection signal Vdet.

The drive electrode driver 14 sequentially supplies a touch drive signalVcomAC to two partial detection regions RTk and RTk+1 in the touchdetection period Pt ((A) in FIG. 35). The touch drive signal VcomAC istransmitted to the touch detection electrode TDL via the capacitance,and the touch detection signal Vdet thereby changes ((B) in FIG. 35).The A/D convertor 43 performs A/D conversion on the output signal of theamplifier 42 to which the touch detection signal Vdet is input in asampling timing is synchronized with the touch drive signal VcomAC ((B)in FIG. 35).

Thus, the display device with a touch detection function 1 performs thetouch detection operation in the partial detection regions RTk and RTk+1in each touch detection period Pt.

Timings of Memory Write WM and Display Drive DD

Timings of the memory write WM and the display drive DD will beexplained next.

FIG. 36 is a timing chart of memory write WM and memory read (displaydrive DD) in the display device with a touch detection function. Thememory 11 a sequentially writes data of one-tenth of the videoinformation for one frame by each one horizontal line (memory write WM).The memory 11 a sequentially reads the written data by each onehorizontal line before the data is erased by being overwritten. Thedisplay drive DD is performed based on the read data. In other words,the display drive DD corresponds to a read of data from the memory(memory read).

The display device with a touch detection function 1 sets the timings ofthe memory write WM and memory read (display drive DD) so that data canbe safely read before the data written to the memory 11 a is erased bybeing overwritten. Specifically, for example, the data in the top row ofa portion P1 is written at a timing tw1, and is then erased by writingthe next data at a timing tw2. Therefore, a timing tr1 of the memoryread (display drive DD) of the data needs to be set in between thetiming tw1 and the timing tw2. Moreover, for example, the data in thebottom row of the portion P1 is written at the timing tw2, and is thenerased by writing the next data at a timing tw3. Therefore, a timing tr2of the memory read (display drive DD) of the data needs to be set inbetween the timing tw2 and the timing tw3.

For example, the timing tr1 is preferably set near the midpoint betweenthe timing tw1 and the timing tw2 in consideration of an operationtiming margin. Likewise, the timing tr2 is preferably set near themidpoint between the timing tw2 and the timing tw3.

FIG. 37 is another timing chart of the memory write WM and the memoryread (display drive DD) in the display device with a touch detectionfunction, where (A) represents a case where a timing of the displaydrive DD is earlier, and (B) represents a case where a timing of thedisplay drive DD is later.

As illustrated in (A) in FIG. 37, in the case where a timing of thedisplay drive DD is earlier, for example, the data in the bottom row ofthe portion P1 is read at the timing tr2 right after the data is writtenat the timing tw2, and the timing margin is therefore reduced. On theother hand, as illustrated in (B) in FIG. 37, in the case where a timingof the display drive DD is later, for example, the data in the top rowof the portion P2 is read at the timing tr1 right before the next datais written at the timing tw2, and the timing margin is therefore reducedas well.

Consequently, as illustrated in FIG. 36, the timings of the memory writeWM and the display drive DD are preferably set so that the time from thetiming tr1 to the timing tw2 is made substantially equal to the timefrom the timing tw2 to the timing tr2. This enables the timing margin tobe increased.

Prevention of Malfunction in Touch Detection Operation

In the capacitive touch panel, noise (disturbance noise) caused by aninverter fluorescent lamp, an AM wave, an AC power supply, or so may bepropagated to the touch panel, thereby causing a malfunction. Themalfunction is caused by the fact that a signal (touch signal) relatedto the presence or absence of a touch cannot be discriminated from thedisturbance noise. The display device with a touch detection function 1can change the frequency of the touch drive signal VcomAC independentlyfrom the display drive, and can therefore suppress the malfunction.Details thereof are explained below.

(A) and (B) in FIG. 38 are timing charts of touch detection operationwhen the frequency of the touch drive signal VcomAC is high, and (C) and(D) in FIG. 38 are timing charts of touch detection operation when thefrequency of the touch drive signal VcomAC is low. In FIG. 38, (A) and(C) represent waveforms of the drive signal Vcom, and (B) and (D)represent waveforms of the touch detection signal Vdet.

As illustrated in (A) and (C) in FIG. 38, the display device with atouch detection function 1 can changes the frequency of the touch drivesignal VcomAC and also changes the sampling frequency in the A/Dconvertor 43. This enables reduction in the possibility of themalfunction in the touch detection operation caused by the disturbancenoise.

In other words, when the frequency of the disturbance noise is aroundthe integral multiple of a sampling frequency fs and the A/D conversionis performed on the disturbance noise by A/D convertor 43, thedisturbance noise appears as so-called folding noise near a frequency 0.Thereby the folding noise is mixed with a touch signal near thefrequency 0, and therefore the touch signal and the noise signal cannotbe discriminated from each other. The display device with a touchdetection function 1 can change the frequency of the touch drive signalVcomAC and the sampling frequency of the A/D convertor 43, and cantherefore select a condition unaffected by the disturbance noise toperform touch detection.

In the display device with a touch detection function 1, the memory 11 areads the data of one-tenth of the written video information for oneframe at a speed higher than that of the write to reduce the displayperiod Pd, thereby ensuring the touch detection period Pt. The displaydevice with a touch detection function 1 then effectively uses the touchdetection period Pt ensured in the above manner to change the frequencyof the touch drive signal VcomAC, thereby preventing the malfunction inthe touch detection operation.

Operation in Sleep Mode

Operation of the display device with a touch detection function 1 insleep mode will be explained next. FIG. 39 is a flowchart of operationof the display device with a touch detection function in sleep mode.FIG. 40 is an explanatory diagram illustrating a timing waveform exampleof the display device with a touch detection function. (A) illustratedin FIG. 40 represents a waveform of the scan signal Vscan. (B)illustrated in FIG. 40 represents a waveform of the pixel signal Vpix.(C) illustrated in FIG. 40 represents waveforms of the drive signalsVcom.

When the process illustrated in FIG. 39 is started, at first, thetouch-detection controller 100 waits until proximity or contact of anobject such as a finger with the touch detection electrode TDL isdetected at Step S101. The touch-detection controller 100 can detect theproximity or contact of the object with the touch detection electrodeTDL using the above-described self-capacitance method.

When the proximity or contact of the object with the touch detectionelectrode TDL is detected, then at Step S102, the touch-detectioncontroller 100 transmits a scan command for scanning the driveelectrodes COML of the display unit with a touch detection function 10to the controller 100. The controller 100 that receives the scan commandstarts scanning, at Step S103, the drive electrodes COML of the displayunit with a touch detection function 10 driven at a low voltage (powersupply voltage Vcc). That is, the controller 100 operates the sourcedriver 13, the drive electrode driver 14, and the gate driver 100D atthe power supply voltage Vcc to start scanning the drive electrodes COMLof the display unit with a touch detection function 10.

The reason that, at Step S103, the controller 100 operates the gatedriver 100D instead of the gate driver 12 to scan the drive electrodesCOML of the display unit with a touch detection function 10 is asfollows. The gate driver 12 is a circuit that operates at the powersupply voltage Vdd generated by the booster circuit 70 in order tooperate the TFT elements Tr of the liquid crystal display unit 20 at ahigh speed and perform image display at a high speed. In the sleep mode,the booster circuit 70 preferably suspends its operation in order toreduce power consumption. The booster circuit 70 has a time lag of abouthundreds of milliseconds from the start of the operation to the outputof the power supply voltage Vdd. Therefore, if the controller 100 causesthe booster circuit 70 to operate and also causes the gate driver 12 tooperate so as to scan the drive electrodes COML of the display unit witha touch detection function 10, a time lag of about hundreds ofmilliseconds occurs. Therefore, the controller 100 operates the gatedriver 100D that operates at the constantly supplied power supplyvoltage Vcc and scans the drive electrodes COML of the display unit witha touch detection function 10. This enables the display device with atouch detection function 1 to suppress the time lag in touch detectionin the sleep mode.

Referring to FIG. 40, the gate driver 100D changes the scan signal Vscanfrom the low level to the high level at a timing t50 ((A) in FIG. 40).Before this operation, the source driver 13 sets the pixel signal Vpixto a predetermined value, e.g., 0V ((B) in FIG. 40). Thereby 0V iswritten to pixels Pix (sub-pixels SPix). More specifically, the pixelelectrodes are is set to 0V. Thereafter, the gate driver 100D changesthe scan signal Vscan from the high level to the low level at a timingt51 ((A) in FIG. 40). Thereby the values of the pixels Pix (sub-pixelsSPix) are determined as 0V. More specifically, the potentials of thepixel electrodes 22 are determined as 0V.

Thereafter, the drive electrode driver 14 applies the touch drive signalVcomAC as a drive signal Vcom (B(k)) to the drive electrodes COML duringtimings t52 to t53, applies the touch drive signal VcomAC as a drivesignal Vcom (B(k+1)) to the drive electrodes COML during timings t54 tot55, and applies the touch drive signal VcomAC as a drive signal Vcom(B(k+2)) to the drive electrodes COML during timings t56 to t57. Thedrive electrodes COML are thereby scanned, and the touch-detectioncontroller 100 can detect coordinates of a touch or a gesture using themutual capacitance method between the drive electrodes COML and thetouch detection electrode TDL.

The reason that the pixel signal Vpix (herein, 0V) is written to thepixels Pix (sub-pixels SPix) at the timings t50 to t51 before the touchdrive signal VcomAC as the drive signal Vcom is applied to the driveelectrodes COML at the timings t52 to t57 is as follows. Because theimage display is not performed in the sleep mode, the values of thepixels Pix (sub-pixels SPix) are undefined. More specifically, thepotentials of the pixel electrodes 22 are undefined. When the touchdrive signal VcomAC as the drive signal Vcom is applied to the driveelectrodes COML in this state, an unexpected voltage is applied to theliquid crystal elements LC, and burn-in may thereby occur in the displayunit with a touch detection function 10. The burn-in is temporary andtherefore disappears after the elapse of a certain period of time.However, images may become difficult to see or an operator may feel asense of incongruity until the burn-in disappears. Therefore, by writingthe pixel signal Vpix (herein, 0V) to the pixels Pix (sub-pixels SPix)before the touch drive signal VcomAC as the drive signal Vcom is appliedto the drive electrodes COML, the values of the pixels Pix (sub-pixelsSPix) are stabilized, the potentials of the pixel electrodes 22 arestabilized, application of the unexpected voltage to the liquid crystalelement LC is prevented, and occurrence of the burn-in can be prevented.This enables the display device with a touch detection function 1 tosuppress the images from becoming difficult to see and the operator fromfeeling the sense of incongruity.

The pixel signal Vpix to be written to the pixels Pix (sub-pixels SPix)is not limited to 0V (low level), and therefore it may be a high level(power supply voltage Vcc) or may be an intermediate between the highlevel and the low level. For example, when the display unit with a touchdetection function 10 is a normally white display unit, a high-levelpixel signal Vpix is written to the pixels Pix (sub-pixels SPix), andthe display screen of the display unit with a touch detection function10 is thereby changed to black, which allows the operator to bedifficult to feel a sense of incongruity. Alternatively, for example,when the display unit with a touch detection function 10 is a normallyblack display unit, a low-level pixel signal Vpix is written to thepixels Pix (sub-pixels SPix), and the display screen of the display unitwith a touch detection function 10 will be black, which allows theoperator to be difficult to feel a sense of incongruity.

Referring again to FIG. 39, the touch-detection controller 100 proceedsthe process to Step S105 when a predetermined gesture (e.g., a swipewith a predetermined length in a predetermined direction) is detected atStep S104, and proceeds the process to Step S101 when a predeterminedgesture is not detected.

When a predetermined gesture is detected at Step S104, then at StepS105, the touch-detection controller 100 transmits a command to theapplication processor. At Step S106, the application processor havingreceived the command transmits a sleep release command to the displaydevice with a touch detection function 1. More specifically, theapplication processor transmits the sleep release command to the controlunit 11 of the display device with a touch detection function 1. Thedisplay device with a touch detection function 1 having received thesleep release command shifts from the sleep mode to the normal operationmode at Step S107. At this time, the control unit 11 of the displaydevice with a touch detection function 1 starts the operation of thebooster circuit 70 and the backlight. This enables the display devicewith a touch detection function 1 to perform image display.

Effects

As explained above, the display device with a touch detection function 1according to the first embodiment writes the pixel signal Vpix to thepixels Pix (sub-pixels SPix) in the sleep mode before the touch drivesignal VcomAC is applied to the drive electrodes COML, and therebystabilizes the values of the pixels Pix (sub-pixels SPix) and stabilizesthe potentials of the pixel electrodes 22. Thus, display device with atouch detection function 1 can prevent the unexpected voltage from beingapplied to the liquid crystal elements LC and the burn-in fromoccurring. This enables the display device with a touch detectionfunction 1 to suppress the images from becoming difficult to see and theoperator from feeling the sense of incongruity.

The display device with a touch detection function 1 operates the gatedriver 100D that operates at the power supply voltage Vcc in the sleepmode to scan the drive electrodes COML of the display unit with a touchdetection function 10. This enables the display device with a touchdetection function 1 to suspend the booster circuit 70 and therebyreduce the power consumption and suppress the time lag in touchdetection.

In the display panel with a touch detection function according to thefirst embodiment, the display wiring LDC for supplying the display drivevoltage VcomDC to the drive electrodes COML and the touch wiring LAC forsupplying the touch drive signal VcomAC to the drive electrodes COML arepulled around to frame areas. For example, in the liquid crystal displayunit using the liquid crystal in the horizontal electric field mode suchas FFS, the display function layer tends to operate more stably byarranging the display wirings LDC nearer to the pixels corresponding tothe respective color areas 32R, 32G, and 32B. Therefore, the selectionswitch SW1 (SW2, SW3, SW4) is arranged between the touch wiring LAC andthe display wiring LDC. The selection switch SW includes the couplingconductors Q1, Q2, and Q3 in a through hall having different layers. Theselection switch SW1 (SW2, SW3, SW4) includes the switches COMSWprovided for each drive electrode COML, and all the switches COMSWoperate for each drive electrode COML according to the switch controlsignals Ssw and Sxsw to couple the touch wiring LAC and the driveelectrode COML, and applies the touch drive signal VcomAC to the driveelectrode COML. Thus, by increasing the number of coupling conductorsQ1, Q2, and Q3 for supplying electric power, coupling resistance of theselection switch SW1 can be reduced.

The touch wiring LAC has a predetermined coupling resistance componentof the selection switch SW1 and a parasitic capacitance of the driveelectrodes COML belonging to the drive electrode block B supplied withthe drive signal VcomAC via the touch wiring LAC. Therefore, in thedrive electrode block B arranged in a position apart from the COG 19(drive-signal generating unit), the transition time of a pulse of thedrive signal VcomAC may become long. On the other hand, in the selectionswitch SW1 (SW2, SW3, SW4) according to the first embodiment, aplurality of CMOS switches CMOS1 of the switch COMSW and a plurality ofCMOS switches CMOS2 of the switch COMSW are respectively provided foreach drive electrode COML, and each units of the CMOS switches CMOS1 andeach units of the CMOS switches CMOS2 are respectively coupled inparallel to each other between the touch wiring LAC and the driveelectrode COML. Therefore, all the switches operate for each driveelectrode COML according to the switch control signal as a selectionsignal to couple the touch wiring LAC and the drive electrode COML, sothat the touch drive signal VcomAC can be applied thereto. The displaydevice with a touch detection function 1 according to the firstembodiment can then reduce the coupling resistance of the switch SW1. Asa result, the display device with a touch detection function 1 accordingto the first embodiment can suppress the possibility that the transitiontime of a pulse of the drive signal VcomAC may become long in the driveelectrode block B arranged near an end portion of the touch wiring LAC.

Comparative Example

Advantageous effects of the present embodiment will be explained next ascompared with a display device with a touch detection function 1Raccording to a comparative example. The display device with a touchdetection function 1R performs both of the display operation and thetouch detection operation in one horizontal period (1H). The rest of theconfiguration is the same as these of the present embodiment (FIG. 1,etc.).

FIG. 41 is a timing chart of display operation and touch detectionoperation in the display device with a touch detection functionaccording to the comparative example, where (A) to (D) represent a casein which the time of the horizontal period (1H) is made short, and (E)to (H) represent a case in which the time of the horizontal period (1H)is made long. In FIG. 41, (A) and (E) represent waveforms of the scansignal Vscan, (B) and (F) represent waveforms of the image signal Vsig,(C) and (G) represent waveforms of the drive signal Vcom, and (D) and(H) represent waveforms of the touch detection signal Vdet.

In the display device with a touch detection function 1R according tothe present comparative example, the touch detection period Pt and thedisplay period Pd are provided in one horizontal period (1H). In otherwords, the display device with a touch detection function 1R firstperforms the touch detection operation in the touch detection period Pt,and then performs the display operation in the display period Pd.

During the touch detection operation according to the presentcomparative example, first of all, the drive electrode driver 14 appliesa pulse P to the drive electrodes COML belonging to the partialdetection region RTk in the touch detection period Pt ((C) and (G) inFIG. 41). The pulse P transmits to the touch detection electrode TDL viathe capacitance, and the touch detection signal Vdet thereby changes((D) and (H) in FIG. 41). The A/D convertor 43 performs the A/Dconversion on the output signal of the amplifier 42 to which the touchdetection signal Vdet is input in the sampling timing is synchronizedwith the pulse P ((D) and (H) in FIG. 41). The display device with atouch detection function 1R thereby performs the touch detectionoperation in the partial detection region RTk. The display operation isthe same as that of the display device with a touch detection function 1according to the present embodiment.

As illustrated in FIG. 41, the display device with a touch detectionfunction 1R according to the present comparative example changes thetime of the one horizontal period (1H) and changes the sampling timingin the A/D convertor 43 in synchronization with the changed time, andcan thereby reduce the risk of malfunction in the touch detectionoperation caused by disturbance noise. In this case, however, the timingof supplying the video signal to the display device with a touchdetection function 1R is different from the actual display timing, andtherefore a frame memory is required. In addition, because the time ofthe one horizontal period (1H) is changed, the display quality maydecrease. Furthermore, because the time of the one horizontal period(1H) cannot be changed so much caused by restriction from the displayoperation, malfunction in the touch detection operation may not besufficiently reduced.

Meanwhile, the display device with a touch detection function 1according to the present embodiment is configured to perform displaydrive for each partial display region RD, and therefore the storagecapacity of the memory 11 a can be reduced to about a data amount in thepartial display region RD.

The display device with a touch detection function 1 is configured tochange the frequency of the touch drive signal VcomAC in the touchdetection period Pt while keeping the time of the touch detection periodPt and the time of the display period Pd constant. Thereby the time ofthe one horizontal period (1H) in the display period Pd can be keptconstant, thus possible decrease of the display quality can be reduced.The display device with a touch detection function 1 can easily andgreatly change the frequency of the touch drive signal VcomAC withouthaving constraint from the display operation, and can therefore reducemalfunction in the touch detection operation as compared with the caseof the display device with a touch detection function 1R according tothe present comparative example.

In other words, in the display device with a touch detection function 1Raccording to the present comparative example, the touch detection periodPt is provided in the one horizontal period (1H), and therefore theoperation capable of being performed in the limited short period of timeis limited. Put another way, the display device with a touch detectionfunction 1R has low flexibility for the touch detection operation.

Meanwhile, in the display device with a touch detection function 1according to the present embodiment, the memory 11 a reads the writtendata of one-tenth of the video information for one frame at a speedhigher than that of the write, so that the display period Pd is madeshorter and the touch detection period Pt is thereby ensured. That is,the display device with a touch detection function 1 can ensure a largeblock of time for the touch detection operation, and therefore theflexibility for the touch detection operation can be increased.

As explained above, the present embodiment is configured to performdisplay drive for each partial display region, which enables to suppressthe storage capacity of the memory to be low.

The present embodiment is also configured to read data from the memoryat a speed higher than a data write speed, which enables to ensure alarge block of time for the touch detection operation, which enables toincrease the flexibility of the touch detection operation.

The present embodiment is further configured to change the frequency ofthe detection signal for touch in the touch detection period of thislarge block of time, which enables to reduce the risk of a malfunctionof the touch detection operation without affecting the displayoperation.

Modification 1-1

In the present embodiment, the touch detection scanning is performed ata speed twice as high as that of the display scanning; however, theembodiment is not limited thereto. Therefore, instead of this, forexample, it may be performed at a speed less than twice the speed of thedisplay scanning or may be performed at a speed higher than twice thespeed thereof. FIG. 42 is a diagram schematically illustrating operationof the display device with a touch detection function when a touchdetection scanning is performed at a speed four times as high as that ofthe display scanning. In this example, the drive electrode driver 14sequentially supplies the touch drive signal VcomAC to the four partialdetection regions RT in the touch detection period Pt. Thereby, thetouch detection scanning can be performed four times during oneperformance of the display scanning.

Modification 1-2

In the present embodiment, the partial display region RT and the partialdetection region RD are obtained by dividing the display surface and thetouch detection surface into 10 portions respectively; however, theembodiment is not limited thereto. Therefore, for example, a size of thepartial display region RD and a size of the partial detection region RTmay be different from each other. FIG. 43 is a diagram schematicallyillustrating operation of the display device with a touch detectionfunction when the size of the partial detection region RT is set to halfof the size of the partial display region RD. In this example, thepartial display region RD is obtained by dividing the display surfaceinto 10 portions, and the partial detection region RT is obtained bydividing the touch detection surface into 20 portions.

Modification 1-3

In the present embodiment, the memory 11 a temporarily stores thereindata in one partial display region RD; however, the embodiment is notlimited thereto. Therefore, instead of this, for example, the memory 11a may temporarily store therein an amount of data in a plurality ofpartial display regions RD. FIG. 44 is a diagram schematicallyillustrating operation of the display device with a touch detectionfunction when data in two partial display regions RD are temporarilystored. Also in this case, the storage capacity of the memory can besuppressed to be low as compared with that of the frame memory.

Modification 1-4

In the present embodiment, when performing touch detection operation, adrive electrode COML is driven and scanned in each partial detectionregion RT that includes a predetermined number of drive electrodes COML;however, the embodiment is not limited thereto. Therefore, instead ofthis, for example, the predetermined number of drive electrodes COML maybe simultaneously driven, and the driven drive electrodes COML may beshifted one by one to be thereby scanned. Details thereof are explainedbelow.

FIG. 45 to FIG. 47 are diagrams schematically illustrating examples ofthe touch detection operation in the display device with a touchdetection function. A drive electrode driver 14D according to thepresent modification simultaneously applies the touch drive signalVcomAC to a predetermined number of drive electrodes COML. Specifically,the drive electrode driver 14D simultaneously applies the touch drivesignal VcomAC to the predetermined number (five in this example) ofdrive electrodes COML (shaded portions). The drive electrode driver 14Dthen shifts the drive electrodes COML, to which the touch drive signalVcomAC is applied, one by one, and thereby performs touch detectionscanning. In this example, the drive electrode driver 14D simultaneouslyapplies the touch drive signal VcomAC to the five drive electrodes COML;however, the embodiment is not limited thereto. Therefore, instead ofthis, the drive electrode driver 14D may simultaneously apply the touchdrive signal VcomAC to four or less or six or more of drive electrodesCOML. In this example, the drive electrode driver 14D shifts the driveelectrodes COML, to which the touch drive signal VcomAC is applied, oneby one; however, the embodiment is not limited thereto. Therefore,instead of this, the drive electrode driver 14D may shift the driveelectrodes by two or more numbers each time.

Modification 1-5

In the present embodiment, the storage capacity of the memory 11 acorresponds to one-tenth of the video information for one frame;however, the embodiment is not limited thereto. Therefore, instead ofthis, for example, the memory capacity may correspond to one-twentiethof the video information for one frame or may correspond to one-fifth ofthe video information for one frame.

Modification 1-6

In the present embodiment, when performing display operation, the driveelectrode driver 14 applies the display drive voltage VcomDC to thedrive electrodes COML; however, the embodiment is not limited thereto.Therefore, instead of this, for example, the drive electrode driver 14may apply an alternating-current drive signal to the drive electrodesCOML, i.e., may perform so-called a COM inversion drive.

Modification 1-7

In the present embodiment, it is configured to provide the sourceselector 13S and separate the pixel signal Vpix from the image signalVsig supplied from the source driver 13 to supply the pixel signal Vpixto the liquid crystal display unit 20; however, the embodiment is notlimited thereto. Therefore, instead of this, the source driver 13 maydirectly supply the pixel signal Vpix to the liquid crystal display unit20 without providing the source selector 13S.

Modification 1-8

In the present embodiment, it is configured to alternately perform theimage display in the partial display region RD and the touch detectionin the partial detection region RT; however, the embodiment is notlimited thereto. Therefore, instead of this, it may be configured tocollectively perform image display for one screen (one frame) andperform touch detection of the whole touch detection area before orafter the image display.

1-2. Second Embodiment

A display device with a touch detection function according to a secondembodiment will be explained next. FIG. 48 is a diagram of an example ofa touch detecting unit of the display device with a touch detectionfunction according to the second embodiment. FIG. 49 and FIG. 50 arediagrams of a detecting unit of the display device with a touchdetection function according to the second embodiment.

The touch detecting unit according to the first embodiment detects thepresence or absence of a touch using the self-capacitance method in thesleep mode. Meanwhile, the touch detecting unit according to the secondembodiment detects the presence or absence of a touch using the mutualcapacitance method in the sleep mode.

As illustrated in FIG. 48, the touch detecting unit 30 includes aplurality of pairs each of which is formed with a touch detectionelectrode TDLa and a touch detection electrode TDLb.

FIG. 49 is a diagram of a pair of the touch detection electrode TDLa andthe touch detection electrode TDLb and a voltage detector (touchdetecting unit) DET in the sleep mode. The voltage detector DET may bebuilt in the touch-detection controller 100.

In the sleep mode, a switch 211 is tuned on, and the drive signal VcomACis applied to the touch detection electrode TDLa. The touch detectionelectrode TDLa and the touch detection electrode TDLb form a capacitiveelement C4, and the capacitance changes between the case in which thefinger is not in contact with or in proximity to the touch detectionelectrode and the case in which the finger is in contact with or inproximity thereto. The voltage detector DET is coupled to the touchdetection electrode TDLb, and the voltage of the touch detectionelectrode TDLb allows detection of the change in the capacitance formedby the touch detection electrode TDLa and the touch detection electrodeTDLb, i.e., detection as to whether the finger is in contact with or inproximity to the touch detection electrode.

FIG. 50 is a diagram of the pair of the touch detection electrode TDLaand the touch detection electrode TDLb and the voltage detector DET inthe normal operation mode. In the normal operation mode, the switch 211is turned off, and the application of the drive signal VcomAC to thetouch detection electrode TDLa is shut off. A switch 212 is turned on,and the touch detection electrode TDLa is coupled to the voltagedetector DET. Thereby, mutual capacitances are formed between the touchdetection electrode TDLa/the touch detection electrode TDLb and thedrive electrodes COML, respectively. The drive signal VcomAC is appliedto the drive electrodes COML, and the voltage detector DET can detectthe touch based on the voltage of the touch detection electrode TDLa andthat of the touch detection electrode TDLb.

Effects

The touch detecting unit 30 according to the second embodiment candetect the presence or absence of the touch using the mutual capacitancein the sleep mode. This enables the touch detecting unit 30 according tothe second embodiment to detect the presence or absence of the touchwith higher precision than the self-capacitance.

1-3. Third Embodiment

A display device with a touch detection function according to a thirdembodiment will be explained next. FIG. 51 is a diagram of an example ofa module that mounts thereon the display device with a touch detectionfunction according to the third embodiment. The same reference signs areassigned to the same components as these explained in the firstembodiment, and overlapping explanation is therefore omitted.

As illustrated in FIG. 51, the display device with a touch detectionfunction 1 according to the third embodiment includes a gate driver 12Cinstead of the gate driver 12B and the gate driver 100D of the displaydevice with a touch detection function 1 according to the firstembodiment. The gate driver 12C is a circuit that can operate at boththe power supply voltage Vcc and the power supply voltage Vdd. In thesleep mode, the gate driver 12C operates at the power supply voltage Vcc(e.g., about 3V to 5V) and the power supply voltage −Vcc (e.g., about−3V to −5V) which are constantly supplied, and applies the scan signalVscan to the scan line GCL. In the normal operation mode, the gatedriver 12C operates at the power supply voltage Vdd (e.g., about 5V to10V) and the power supply voltage −Vdd (e.g., about −5V to −10V) whichare generated by the booster circuit 70, and applies the scan signalVscan to the scan line GCL.

Effects

The display device with a touch detection function 1 according to thethird embodiment includes the gate driver 12C instead of the gate driver12B and the gate driver 100D of the display device with a touchdetection function 1 according to the first embodiment. This enables thedisplay device with a touch detection function 1 according to the thirdembodiment to narrow the frame Gd, thus downsizing the electronicapparatus.

1-4. Fourth Embodiment

A display device with a touch detection function 1 according to a fourthembodiment will be explained next. FIG. 52 is a diagram of an example ofa control device of the display device with a touch detection functionaccording to the fourth embodiment. FIG. 53 is a block diagram of adrive unit of a drive electrode driver according to the fourthembodiment. FIG. 54 is a block diagram of an arrangement example ofselection switches of the drive electrode driver according to the fourthembodiment. The same reference signs are assigned to the same componentsas these explained in the first embodiment, and overlapping explanationis therefore omitted. FIG. 53 and FIG. 54 explain the configuration ofthe first gate driver 12A side, and the same goes for the configurationof the second gate driver 12B.

As illustrated in FIG. 52, the pixel substrate 2 includes the displayarea Ad which is provided on the surface of the TFT substrate 21 of atranslucent insulating substrate (e.g., a glass substrate) and on whicha number of pixels including liquid crystal cells are arranged in amatrix (in the form of rows and columns), the source driver (horizontaldrive circuit) 13, and the gate drivers (vertical drive circuits) 12A,12B, and 100D. The gate drivers (vertical drive circuits) 12A and 12Bare arranged across the display area Ad, as the first gate driver 12Aand the second gate driver 12B respectively. In the normal operationmode, the first gate driver 12A and the second gate driver 12Balternately apply the vertical scan pulse to the scan lines GCL in thescan direction, and select sub-pixels SPix in the display area Ad row byrow. The first gate driver 12A and the second gate driver 12B arearranged at respective ends of the scan line GCL in its longitudinaldirection, alternately apply the vertical scan pulse to every other scanline GCL, and select pixels in the display area Ad row by row.

Therefore, as illustrated in FIG. 53, on the first gate driver 12A sideor the second gate driver 12B side, the number of the scan lines GCLpassing through the frame Gd across the display area Ad and reaching thefirst gate driver 12A or the second gate driver 12B becomes less.Consequently, in the frame Gd, an odd or an even number of scan linesGCL pass between the display area Ad and the first gate driver 12A/thesecond gate driver 12B. As a result, the CMOS switch CMOS1 of theselection switch SW1 is disposed in an area between scan lines GCL(e.g., between the scan line GCL_(m+1) and the scan line GCL_(m+3)) thatthree-dimensionally intersect the touch wiring LAC (display wiring LDC).For example, the scan lines GCL (e.g., the scan line GCL_(m+1) and thescan line GCL_(m+3)) coupled to the first gate driver 12Athree-dimensionally intersect the touch wiring LAC on the first gatedriver 12A side but do not three-dimensionally intersect the touchwiring LAC on the second gate driver 12B side. The scan lines (e.g., thescan line GCL_(m+2) and the scan line GCL_(m+4)) coupled to the secondgate driver 12B three-dimensionally intersect the touch wiring LAC onthe second gate driver 12B side but do not three-dimensionally intersectthe touch wiring LAC on the first gate driver 12A side. Therefore, adistance between the scan lines GCL three-dimensionally intersecting thetouch wiring LAC (display wiring LDC) becomes wider than a distancebetween adjacent scan lines GCL in the display area Ad. In other words,the distance between the scan lines GCL in the frame Gd is wider thanthe distance between adjacent scan lines GCL in the display area Ad.Because the distance between the scan lines GCL in the frame Gd iswidened, the area where the selection switches SW1 (CMOS switch CMOS1and CMOS switch CMOS2) can be arranged is increased. For example, byincreasing the number of the coupling conductors Q1, Q2, and Q3 or byincreasing the area thereof, coupling resistance of the selection switchSW1 can be reduced.

The selection switch SW1 is disposed not only in a frame area Gd on thefirst gate driver 12A side but also in a frame area Gd on the secondgate driver 12B side. The selection switch SW1 disposed in the framearea Gd on the second gate driver 12B side can select coupling betweenthe touch wiring LAC arranged on the second gate driver 12B side and thedrive electrode COML and coupling between the display wiring LDC and thedrive electrode COML. In this case, selection switches coupled to thesame drive electrode COML, of the selection switches on the first gatedriver 12A side and the selection switches on the second gate driver 12Bside, select wirings (touch wirings LAC or display wirings LDC) of thesame type as each other respectively. For example, when the selectionswitch SW1 on the first gate driver 12A side selects coupling betweenthe touch wiring LAC and the drive electrode COML, the selection switchSW1 on the second gate driver 12B side, which is coupled to the samedrive electrode COML as the selection switch SW1 on the first gatedriver 12A side, selects coupling between the touch wiring LAC and thedrive electrode COML. When the selection switch SW1 on the first gatedriver 12A side selects coupling between the display wiring LDC and thedrive electrode COML, the selection switch SW1 on the second gate driver12B side, which is coupled to the same drive electrode COML as theselection switch SW1 on the first gate driver 12A side, selects couplingbetween the display wiring LDC and the drive electrode COML.

Effects

As is the first embodiment, when the selection switch SW1 is disposed inbetween the scan lines GCL corresponding to one pitch of the sub-pixelsSPix, and if the pixel pitch is narrowed in association with higherresolution, the coupling resistance of the selection switch SW1 islikely to increase. On the other hand, the display device with a touchdetection function 1 according to the fourth embodiment can arrange theselection switch SW1 in a distance wider than the distance between thescan lines GCL corresponding to one pitch of the sub-pixels SPix.Therefore, even if the pixel pitch is made narrow due to higherresolution, the coupling resistance of the switch SW1 can be kept low.In addition, by increasing the number of the coupling conductors Q1, Q2,and Q3 supplying power, the coupling resistance of the selection switchSW1 can be reduced.

The touch wiring LAC has a predetermined coupling resistance componentof the switch SW1 and a parasitic capacitance of the drive electrodesCOML belonging to the drive electrode block B supplied with the drivesignal VcomAC via the touch wiring LAC. Therefore, in the driveelectrode block B arranged in a position apart from the COG 19(drive-signal generating unit), the transition time of a pulse of thedrive signal VcomAC may become long. On the other hand, the selectionswitch SW1 (SW2, SW3, SW4) according to the fourth embodiment has aplurality of CMOS switches CMOS1 and CMOS switches CMOS2 of the switchCOMSW provided for each drive electrode COML. The CMOS switch CMOS1 andthe CMOS switch CMOS2 are coupled in parallel to each other between thetouch wiring LAC and the drive electrode COML, and therefore all theswitches operate for each drive electrode COML according to the switchcontrol signal as a selection signal to connect the touch wiring LAC andthe drive electrode COML, thus applying the touch drive signal VcomACthereto. In the display device with a touch detection function 1according to the fourth embodiment, the coupling resistance of theswitch S1 is reduced, and the possibility that the transition time ofthe pulse of the drive signal VcomAC may become long in the driveelectrode block B arranged near the end portion of the touch wiring LACis suppressed.

The switch SW1 according to the fourth embodiment can be made small in adirection parallel to the scan line and can be made large in a directionperpendicular to the scan line. This enables the display device with atouch detection function 1 according to the fourth embodiment to makesmall the width occupied by the switch SW1 in the direction parallel tothe scan line within the frame Gd, i.e., the width Gdv illustrated inFIG. 7.

1-5. Fifth Embodiment

A display device with a touch detection function 1 according to a fifthembodiment will be explained next. FIG. 55 is a block diagram of a driveunit of a drive electrode driver in the display device with a touchdetection function according to the fifth embodiment. FIG. 56 is a blockdiagram of an arrangement example of selection switches of the driveelectrode driver in the display device with a touch detection functionaccording to the fifth embodiment. The same reference signs are assignedto the same components as these explained in the first to the fourthembodiments, and overlapping explanation is therefore omitted. FIG. 55and FIG. 56 explain the drive electrode driver on the first gate driver12A side, and the same goes for the configuration of the second gatedriver 12B.

As illustrated in FIG. 52, also in the fifth embodiment, the pixelsubstrate 2 includes the display area Ad which is provided on thesurface of the TFT substrate 21 of a translucent insulating substrate(e.g., a glass substrate) and on which a number of pixels includingliquid crystal cells are arranged in a matrix (in the form of rows andcolumns), the source driver (horizontal drive circuit) 13, and the gatedrivers (vertical drive circuits) 12A, 12B, and 100D. The gate drivers(vertical drive circuits) 12A and 12B are arranged across the displayarea Ad, as the first gate driver 12A and the second gate driver 12Brespectively. In the normal operation mode, the first gate driver 12Aand the second gate driver 12B alternately apply the vertical scan pulseto the scan lines in the scan direction, and select sub-pixels SPix inthe display area Ad row by row.

As illustrated in FIG. 55, on the first gate driver 12A side or thesecond gate driver 12B side, the number of the scan lines GCL passingthrough the frame Gd across the display area Ad and reaching the firstgate driver 12A or the second gate driver 12B becomes less. A pluralityof scan lines GCL_(m+2) and GCL_(m+4) (a plurality of scan linesGCL_(m+6) and GCL_(m+8)) are arranged in between adjacent switchesCOMSW. This arrangement coincides with one pitch between the gate shiftregisters 120SR of the first gate driver 12A (second gate driver 12B).The gate shift register 120SR controls the two scan lines GCL as a pair.Therefore, in the selection switch SW1, the switch COMSW corresponds tofour pitches of the sub-pixels SPix, and a repetitive pitch correspondsto eight sub-pixels SPix. Consequently, in the frame Gd, an odd or aneven number of scan lines GCL pass between the display area Ad and thefirst gate driver 12A/the second gate driver 12B. As a result, the CMOSswitch CMOS2 three-dimensionally intersects the touch wiring LAC(display wiring LDC) and is disposed in an area between the scan linesGCL (e.g., between the scan line GCL_(m+4) and the scan line GCL_(m+6))adjacent to the CMOS switch CMOS1 and the CMOS switch CMOS2. Forexample, the scan lines GCL (e.g., the scan line GCL_(m+2), the scanline GCL_(m+4), the scan line GCL_(m+6), and the scan line GCL_(m+8))coupled to the first gate driver 12A three-dimensionally intersect thetouch wiring LAC on the first gate driver 12A side but do notthree-dimensionally intersect the touch wiring LAC on the second gatedriver 12B side. The scan lines (e.g., the scan line GCL_(m+1), the scanline GCL_(m+3), the scan line GCL_(m+5), and the scan line GCL_(m+7))coupled to the second gate driver three-dimensionally intersect thetouch wiring LAC on the second gate driver side but do notthree-dimensionally intersect the touch wiring LAC on the first gatedriver side. Therefore, a distance between the scan lines GCLthree-dimensionally intersecting the touch wiring LAC (display wiringLDC) becomes wider than a distance between adjacent scan lines GCL inthe display area Ad. Because the distance between the scan lines GCL inthe frame Gd is widened, the area where the selection switches SW1 (CMOSswitch CMOS1 and CMOS switch CMOS2) can be arranged is increased. Forexample, by increasing the number of the coupling conductors Q1, Q2, andQ3 or by increasing the area thereof, the coupling resistance of theselection switch SW1 can be reduced.

The selection switch SW1 is disposed not only in the frame area Gd onthe first gate driver 12A side but also in the frame area Gd on thesecond gate driver 12B side. The selection switch SW1 disposed in theframe area Gd on the second gate driver 12B side can select couplingbetween the touch wiring LAC and the drive electrode COML and couplingbetween the display wiring LDC and the drive electrode COML, which arearranged on the second gate driver 12B side. In this case, selectionswitches coupled to the same drive electrode COML, of the selectionswitches on the first gate driver 12A side and the selection switches onthe second gate driver 12B side, select wirings (touch wiring LAC ordisplay wiring LDC) of the same type as each other respectively. Forexample, when the selection switch SW1 on the first gate driver 12A sideselects coupling between the touch wiring LAC and the drive electrodeCOML, the selection switch SW1 on the second gate driver 12B side, whichis coupled to the same drive electrode COML as the selection switch SW1on the first gate driver 12A side, selects coupling between the touchwiring LAC and the drive electrode COML. When the selection switch SW1on the first gate driver 12A side selects coupling between the displaywiring LDC and the drive electrode COML, the selection switch SW1 on thesecond gate driver 12B side, which is coupled to the same driveelectrode COML as the selection switch SW1 on the first gate driver 12Aside, selects coupling between the display wiring LDC and the driveelectrode COML.

Effects

As is the first embodiment, when the selection switch SW1 is disposed inbetween the scan lines GCL corresponding to one pitch of the sub-pixels,and if the pixel pitch is narrowed in association with higherresolution, the coupling resistance of the selection switch SW1 islikely to increase. On the other hand, in the display device with atouch detection function 1 according to the fifth embodiment, theselection switch SW1 can be arranged in a distance wider than thedistance between the scan lines GCL corresponding to one pitch of thesub-pixels SPix. Therefore, even if the pixel pitch is made narrow dueto higher resolution, the coupling resistance of the switch SW1 can bekept low. In addition, by increasing the number of the couplingconductors Q1, Q2, and Q3 supplying power, the coupling resistance ofthe selection switch SW1 can be reduced.

The touch wiring LAC has a predetermined coupling resistance componentof the switch SW1 and a parasitic capacitance of the drive electrodesCOML belonging to the drive electrode block B supplied with the drivesignal VcomAC via the touch wiring LAC. Therefore, in the driveelectrode block B arranged in a position apart from the COG 19(drive-signal generating unit), the transition time of a pulse of thedrive signal VcomAC may become long. On the other hand, the selectionswitch SW1 (SW2, SW3, SW4) according to the fifth embodiment has aplurality of CMOS switches CMOS1 and CMOS switches CMOS2 of the switchCOMSW provided for each drive electrode COML. The CMOS switch CMOS1 andthe CMOS switch CMOS2 are coupled in parallel to each other between thetouch wiring LAC and the drive electrode COML, and therefore all theswitches operate for each drive electrode COML according to the switchcontrol signal as a selection signal to connect the touch wiring LAC andthe drive electrode COML, so that the touch drive signal VcomAC can beapplied thereto. The display device with a touch detection function 1according to the fifth embodiment reduces the coupling resistance of theswitch S1 and thereby suppresses the possibility that the transitiontime of the pulse of the drive signal VcomAC may become long in thedrive electrode block B arranged near the end portion of the touchwiring LAC.

The switch SW1 according to the fifth embodiment can be made small in adirection parallel to the scan line and can be made large in a directionperpendicular to the scan line. This enables the display device with atouch detection function 1 according to the fifth embodiment to makesmall a width occupied by the switch SW1 in the direction parallel tothe scan line within the frame Gd, i.e., the width Gdv illustrated inFIG. 7.

1-6. Sixth Embodiment

A display device with a touch detection function according to a sixthembodiment will be explained next. FIG. 57 is a diagram of an example ofa module that mounts thereon the display device with a touch detectionfunction according to the sixth embodiment.

As illustrated in FIG. 57, the COG 19 is supplied with a power supplyvoltage V1 from a battery, a main substrate of the electronic apparatus,or the like. The power supply voltage V1 is not the power supply voltagefor driving the display unit with a touch detection function 10 but isthe power supply voltage as a low voltage (e.g., 1.8V) for an interfacethat receives a control signal from the touch IC 110 and outputs thecontrol signal to an external power supply IC 200.

The COG 19 is also supplied with the power supply voltage Vcc or Vdd fordriving the display unit with a touch detection function 10 from thepower supply IC 200. The power supply IC 200 is supplied with a powersupply voltage V2 (e.g., +3V, −3V) from the battery, the main substrateof the electronic apparatus, or the like. The power supply IC 200 has afunction of the booster circuit 70 explained in the first embodiment,and boosts the power supply voltage V2 to generate a power supplyvoltage Vcc (e.g., about 3V to 5V) or Vdd (e.g., about 5V to 10V) andsupplies the generated voltage to the COG 19.

The power supply IC 200 is disposed outside the module; however, it maybe disposed inside the module. For example, the power supply IC 200 maybe mounted on the flexible printed wiring board T.

FIG. 58 is a timing chart of operation of the display device with atouch detection function according to the sixth embodiment, where (A)represents a touch detection process of the touch IC, (B) representsoperation of the COG, (C) represents operation timing of the touch IC,(D) represents a TRGT signal as a control signal output from the touchIC to the COG, and (E) represents an output voltage of the power supplyIC.

At an initial timing t60, the touch IC 110 detects a touch using theself-capacitance method of the touch detection electrode TDL ((A) inFIG. 58). The COG 19 is in sleep and is not therefore driving thedisplay unit with a touch detection function 10, but can receive thecontrol signal from the touch IC 110 ((B) in FIG. 58). The TRGT signalis inactive (low level) ((D) in FIG. 58). The power supply IC 200 is insleep and does not perform boosting, and therefore an output voltage is0V.

As illustrated in (C) of FIG. 58, the touch IC 110 detects a touch at apredetermined interval using the self-capacitance method of the touchdetection electrode TDL. The predetermined interval is, for example,about 4 milliseconds (ms). When detecting a touch, the touch IC 110makes the TRGT signal active (high level) at a timing t61. The TRGTsignal is transmitted from the touch IC 110 to the COG 19 via a signalline L1 in FIG. 57.

When the TRGT signal is made active at the timing t61, the COG 19transmits the control signal to the power supply IC 200 via a signalline L2 in FIG. 57 and returns the power supply IC 200 from the sleep.Because the image display is not performed herein, a high power supplyvoltage Vdd is not needed, and therefore the COG 19 causes the powersupply IC 200 to output the power supply voltage Vcc.

When receiving the control signal from the COG 19 at the timing t61, thepower supply IC 200 starts a return operation from the sleep at thetiming t61, starts boosting, and supplies the power supply voltage Vccto the COG 19 at a timing t62 after the elapse of a predetermined delaytime. The predetermined delay time is, for example, about 8 ms to 32 ms.

At the timing t62, the COG 19 uses the power supply voltage Vcc suppliedfrom the power supply IC 200 to start the drive of the drive electrodeCOML. That is, the COG 19 changes the scan signal Vscan from the lowlevel to the high level. Before this operation, the COG 19 sets thepixel signal Vpix to a predetermined value, e.g., 0V. Thereby, the value0V is written to the pixels Pix (sub-pixels SPix). More specifically,the pixel electrodes 22 are set to 0V. Thereafter, the COG 19 changesthe scan signal Vscan from the high level to the low level. Thereby thevalues of the pixels Pix (sub-pixels SPix) are determined as 0V. Morespecifically, the potential of the pixel electrodes 22 is determined as0V. Thereafter, the COG 19 supplies the touch drive signal VcomAC to thedrive electrodes COML to start scanning of the drive electrodes COML.

At a timing t63 after the elapse of a predetermined time from the timingt62, the touch IC 110 detects a gesture at a predetermined intervalusing the mutual capacitance method between the touch detectionelectrode TDL and the drive electrode COML. The predetermined time is,for example, about 32 ms to 64 ms.

When detecting a predetermined gesture, the touch IC 110 transmits acommand to the application processor at a timing t64. The applicationprocessor having received the command transmits a sleep release commandto the COG 19.

At the timing t64, the COG 19 having received the sleep release commandoutputs the control signal for causing the power supply IC 200 to outputthe power supply voltage Vdd to the power supply IC 200. Herein, thehigh power supply voltage Vdd is needed in order to perform imagedisplay at a high speed, and therefore the COG 19 outputs the controlsignal for causing the power supply IC 200 to output the power supplyvoltage Vdd to the power supply IC 200.

The power supply IC 200 starts, at the timing t64, a return operationfrom the sleep and starts boosting, and supplies the power supplyvoltage Vdd at a timing t65 after the elapse of a predetermined delaytime to the COG 19. The predetermined delay time is, for example, about100 ms. At this time, the COG 19 starts operation of the backlight. Thisenables the display device with a touch detection function 1 to performimage display.

At the timing t65, the COG 19 uses the power supply voltage Vdd suppliedfrom the power supply IC 200 to start the drive of the display unit witha touch detection function 10, i.e., the drive of the drive electrodeCOML in order to display of an image and detect a touch. At a timing t66after the elapse of a predetermined time from the timing t65, the touchIC 110 detects a gesture at a predetermined interval using the mutualcapacitance method between the touch detection electrode TDL and thedrive electrode COML. The predetermined time is, for example, about 32ms to 64 ms.

As explained above, the display device with a touch detection function 1returns from the sleep mode to the normal operation mode. If there is notouch input for a predetermined time in the normal operation mode, theapplication processor transmits a sleep command to the COG 19. Whenreceiving the sleep command from the application processor, the COG 19stops the drive of the display unit with a touch detection function 10and terminates the image display and the drive of the drive electrodeCOML, and then causes the power supply IC 200 to sleep (stop boosting).

Effects

According to the present embodiment, the display device with a touchdetection function 1 can directly return the power supply IC 200 fromthe sleep state to the normal state or from the normal state to thesleep state. This enables the display device with a touch detectionfunction 1 to appropriately control the operation of the power supply IC200 and to adequately reduce the power consumption.

Some embodiments and modifications have been explained so far; however,the present disclosure is not limited thereto, and therefore variousmodifications are possible.

The display device with a touch detection function 1 according to theembodiments and modifications can integrate the liquid crystal displayunit 20 using liquid crystal in various modes such as FFS and IPS withthe touch detecting unit 30 to form the display unit with a touchdetection function 10. FIG. 59 is a cross-sectional view of a schematiccross-sectional structure of a display unit with a touch detectionfunction according to a modification. Instead of this, the display unitwith a touch detection function 10 according to the modificationillustrated in FIG. 59 may integrate liquid crystal in various modessuch as twisted nematic (TN), vertical alignment (VA), and electricallycontrolled birefringence (ECB) with the touch detecting unit.

As illustrate in FIG. 59, when the drive electrodes COML are provided inthe counter substrate 3, the touch wiring LAC and the display wiring LDCmay be provided on the counter substrate 3. With this structure, thedistance between the drive electrodes COML and the touch wiring LAC(display wiring LDC) is reduced. The scan line GCL provided on the TFTsubstrate 21 three-dimensionally intersects the touch wiring LAC and thedisplay wiring LDC similarly to the first to the fifth embodiments. As aresult, the touch wiring LAC is disposed in the frame area Gd locatedoutside the display area Ad in the direction perpendicular to the TFTsubstrate 21.

In the embodiments, the so-called in-cell type device, in which theliquid crystal display unit 20 is integrated with the capacitive typetouch detecting unit 30, is provided; however, the embodiments are notlimited thereto. Instead of this type, for example, the on-cell typedevice on which the liquid crystal display unit 20 and the capacitivetype touch detecting unit 30 are mounted may be provided. In the case ofthe on-cell type, the drive electrodes COML of the pixel substrate 2illustrated in FIG. 13 are first drive electrodes COML, and, in additionto this, second drive electrodes COML are provided on the surface of theglass substrate 31 in the counter substrate 3, and the first driveelectrodes COML and the second drive electrodes COML are electricallycoupled to each other. In this case, also, the configuration asexplained above is formed, so that touch detection can be performedwhile suppressing the influence of the external noise and the noise(which corresponds to the internal noise in the embodiments) transmittedfrom the liquid crystal display unit.

2. APPLICATION EXAMPLES

Application examples of the display device with a touch detectionfunction 1 as explained in the embodiments and their modifications willbe explained below with reference to FIG. 60 to FIG. 72. FIG. 60 to FIG.72 are diagrams of examples of an electronic apparatus to which thedisplay device with a touch detection function according to one of theembodiments and modifications thereof is applied. The display devicewith a touch detection function 1 according to the first to the fifthembodiments and the modifications can be applied to electronicapparatuses in all areas such as television devices, digital cameras,notebook personal computers, portable electronic apparatuses such asmobile telephones, or video cameras. In other words, the display devicewith a touch detection function 1 according to the first to the fifthembodiments and the modifications can be applied to electronicapparatuses in all areas that display an externally input video signalor an internally generated video signal as an image or a video.

Application Example 1

The electronic apparatus illustrated in FIG. 60 is a television deviceto which the display device with a touch detection function 1 accordingto the first to the fifth embodiments and the modifications is applied.Examples of the television device include, but are not limited to, avideo display screen unit 510 including a front panel 511 and a filterglass 512. The video display screen unit 510 is the display device witha touch detection function according to the first to the fifthembodiments and the modifications.

Application Example 2

The electronic apparatus illustrated in FIG. 61 and FIG. 62 is a digitalcamera to which the display device with a touch detection function 1according to the first to the fifth embodiments and the modifications isapplied. Examples of the digital camera include, but are not limited to,a light emitting unit 521 for a flash, a display unit 522, a menu switch523, and a shutter button 524. The display unit 522 is the displaydevice with a touch detection function according to the first to thefifth embodiments and the modifications. As illustrated in FIG. 61, thedigital camera has a lens cover 525, and by sliding the lens cover 525,a photographing lens comes out. The digital camera is capable of takingdigital photos by capturing light incident through the photographinglens.

Application Example 3

The electronic apparatus illustrated in FIG. 63 represents an appearanceof a video camera to which the display device with a touch detectionfunction 1 according to the first to the fifth embodiments and themodifications is applied. Examples of the video camera include, but arenot limited to, a main body 531, a lens 532 for photographing a subjectprovided on the front side face of the main body 531, a start/stopswitch 533 in photographing, and a display unit 534. The display unit534 is the display device with a touch detection function according tothe first to the fifth embodiments and the modifications.

Application Example 4

The electronic apparatus illustrated in FIG. 64 is a notebook personalcomputer to which the display device with a touch detection function 1according to the first to the fifth embodiments and the modifications isapplied. Examples of the notebook personal computer include, but are notlimited to, a main body 541, a keyboard 542 for performing an inputoperation of text and the like, and a display unit 543 that displays animage. The display unit 543 is the display device with a touch detectionfunction according to the first to the fifth embodiments and themodifications.

Application Example 5

The electronic apparatus illustrated in FIG. 65 to FIG. 71 is a mobilephone to which the display device with a touch detection function 1according to the first to the fifth embodiments and the modifications isapplied. The mobile phone is the one that has, for example, an upperhousing 551 and a lower housing 552 coupled to each other with aconnecting portion (hinge portion) 553, and that includes a display 554,a sub-display 555, a picture light 556, and a camera 557. The display554 or the sub-display 555 is the display device with a touch detectionfunction according to the first to the fifth embodiments and themodifications.

Application Example 6

The electronic apparatus illustrated in FIG. 72 is a portableinformation terminal that operates as a portable computer, amultifunctional mobile phone, a portable computer capable of performingvoice communication, or as a portable computer capable of performingcommunication, and that is sometimes referred to as so-called asmartphone or a tablet terminal. The portable information terminal has adisplay unit 562 on the surface of, for example, a housing 561. Thedisplay unit 562 is the display device with a touch detection function 1according to the first to the fifth embodiments and the modifications.

3. CONFIGURATION OF PRESENT DISCLOSURE

The present disclosure can also be configured as follows.

(1) A display device with a touch detection function that has a normaloperation mode for performing image display and touch detection and asleep mode for performing touch detection without performing the imagedisplay, comprising:

a display area in which a plurality of pixel electrodes are arranged ina matrix on a substrate;

a drive electrode that is arranged opposite to the pixel electrodes andis divided into a plurality of portions;

a touch detection electrode that is arranged opposite to the driveelectrode and forms a capacitance with the drive electrode;

a display function layer that has an image display function fordisplaying an image in the display area;

a control device that performs image display control, in the normaloperation mode, so as to apply a display drive voltage between the pixelelectrode and the drive electrode based on an image signal to exhibitthe image display function of the display function layer, and performstouch detection control so as to supply a touch drive signal to thedrive electrode;

a touch detecting unit that detects, in the normal operation mode, aposition of an object in proximity to or in contact with the touchdetection electrode based on a detection signal transmitted from thetouch detection electrode; and

a touch-detection controller that detects, in the sleep mode, theproximity of the object to or the contact thereof with the touchdetection electrode, wherein,

when the touch-detection controller detects the proximity of the objectto or the contact thereof with the touch detection electrode in thesleep mode, the control device controls the pixel electrode to apredetermined potential, and thereafter supplies the touch drive signalto the drive electrode.

(2) The display device with a touch detection function according to (1),further comprising:

a booster circuit that boosts a first power supply voltage constantlysupplied from an external device in the normal operation mode togenerate a second power supply voltage, and that suspends the operationin the sleep mode, wherein

the control device uses the second power supply voltage in the normaloperation mode to apply the display drive voltage between the pixelelectrode and the drive electrode, and uses the first power supplyvoltage in the sleep mode to set the pixel electrode to thepredetermined potential.

(3) The display device with a touch detection function according to (2),further comprising:

a plurality of scan lines that are provided in the display area so as tobe extended in a first direction and are supplied with a scan signal;

a plurality of pixel signal lines that are provided in the display areaso as to be extended in a second direction intersecting the firstdirection and are supplied with a pixel signal; and

a plurality of transistors that are provided at respective intersectionsbetween the scan lines and the pixel signal lines, each one of sourcesor of drains of the transistors being coupled to the pixel signal line,each gate thereof being coupled to the scan line, the other one of thesources or of the drains being coupled to the pixel electrode, wherein

the control device supplies, in the sleep mode, the predeterminedpotential to the pixel signal line and uses the first power supplyvoltage to supply the scan signal to the scan line, and supplies, in thenormal operation mode, the pixel signal to the pixel signal line anduses the second power supply voltage to supply the scan signal to thescan line.

(4) The display device with a touch detection function according to (3),wherein

the control device includes:

-   -   a first gate driver that uses the second power supply voltage to        supply the scan signal to the scan line in the normal operation        mode, and    -   a second gate driver that uses the first power supply voltage to        supply the scan signal to the scan line in the sleep mode.

(5) The display device with a touch detection function according to (3),wherein

the control device includes:

-   -   a gate driver that uses the second power supply voltage to        supply the scan signal to the scan line in the normal operation        mode, and uses the first power supply voltage to supply the scan        signal to the scan line in the sleep mode.

(6) The display device with a touch detection function according to (1),wherein, when the touch-detection controller detects the proximity ofthe object to or the contact thereof with the touch detection electrodein the sleep mode,

the control device controls a power supply circuit so as to boost afirst power supply voltage constantly supplied from an external deviceand start generation of a second power supply voltage, and controls thepixel electrode to a predetermined potential using the second powersupply voltage and thereafter supplies the touch drive signal to thedrive electrode.

(7) The display device with a touch detection function according to (6),wherein

in the normal operation mode, the control device controls the powersupply circuit so as to boost the first power supply voltage to generatea third power supply voltage that is a higher voltage than the secondpower supply voltage, and uses the third power supply voltage to applythe display drive voltage between the pixel electrode and the driveelectrode.

(8) The display device with a touch detection function according to (1),wherein

in the sleep mode, the touch-detection controller detects the proximityof the object to or the contact thereof with the touch detectionelectrode using self-capacitance of the touch detection electrode.

(9) The display device with a touch detection function according to (1),wherein

the touch detection electrode is set as a plurality of pairs, and

the touch-detection controller detects, in the sleep mode, the proximityof the object to or the contact thereof with the touch detectionelectrode using mutual capacitance between a pair of the touch detectionelectrodes.

(10) The display device with a touch detection function according to(1), wherein, when a predetermined gesture performed by the object isdetected in the sleep mode, the sleep mode is shifted to the normaloperation mode.

(11) An electronic apparatus including a display device with a touchdetection function that has a normal operation mode for performing imagedisplay and touch detection and a sleep mode for performing touchdetection without performing the image display, wherein the displaydevice with a touch detection function is the display device with atouch detection function according to any one of (1) to (10).

According to the display device with a touch detection function and theelectronic apparatus of the present disclosure, it is possible toprevent the burn-in occurring on the display screen.

It should be understood that various changes and modifications to thepresently preferred embodiments described herein will be apparent tothose skilled in the art. Such changes and modifications can be madewithout departing from the spirit and scope of the present subjectmatter and without diminishing its intended advantages. It is thereforeintended that such changes and modifications be covered by the appendedclaims.

The invention is claimed as follows:
 1. A display device with a touch detection function that has a normal operation mode for performing image display and touch detection and a sleep mode for performing touch detection without performing the image display, comprising: a display area in which a plurality of pixel electrodes are arranged in a matrix on a substrate; a drive electrode that is arranged opposite to the pixel electrodes and is divided into a plurality of portions; a touch detection electrode that is arranged opposite to the drive electrode and forms a capacitance a display function layer that has an image display function for displaying an image in the display area; a control device that performs image display control, in the normal operation mode, so as to apply a display drive voltage between the pixel electrode and the drive electrode based on an image signal to exhibit the image display function of the display function layer, and performs touch detection control so as to supply a touch drive signal to the drive electrode; a touch detecting unit that detects, in the normal operation mode, a position of an object in proximity to or in contact with the touch detection electrode based on a detection signal transmitted from the touch detection electrode; and a touch-detection controller that detects, in the sleep mode, the proximity of the object to or the contact thereof with the touch detection electrode, wherein, when the touch-detection controller detects the proximity of the object to or the contact thereof with the touch detection electrode in the sleep mode, the control device controls a voltage between the drive electrode and the touch detection electrode to be substantially zero, and thereafter supplies the touch drive signal to the drive electrode.
 2. The display device with a touch detection function according to claim 1, further comprising: a booster circuit that boosts a first power supply voltage constantly supplied from an external device in the normal operation mode to generate a second power supply voltage, and that suspends the operation in the sleep mode, wherein the control device uses the second power supply voltage in the normal operation mode to apply the display drive voltage between the pixel electrode and the drive electrode, and uses the first power supply voltage in the sleep mode to set the pixel electrode to a predetermined potential.
 3. The display device with a touch detection function according to claim 2, further comprising: a plurality of scan lines that are provided in the display area so as to be extended in a first direction and are supplied with a scan signal; a plurality of pixel signal lines that are provided in the display area so as to be extended in a second direction intersecting the first direction and are supplied with a pixel signal; and a plurality of transistors that are provided at respective intersections between the scan lines and the pixel signal lines, each one of sources or of drains of the transistors being coupled to the pixel signal line, each gate thereof being coupled to the scan line, the other one of the sources or of the drains being coupled to the pixel electrode, wherein the control device supplies, in the sleep mode, the predetermined potential to the pixel signal line and uses the first power supply voltage to supply the scan signal to the scan line, and supplies, in the normal operation mode, the pixel signal to the pixel signal line and uses the second power supply voltage to supply the scan signal to the scan line.
 4. The display device with a touch detection function according to claim 3, wherein the control device includes: a first gate driver that uses the second power supply voltage to supply the scan signal to the scan line in the normal operation mode, and a second gate driver that uses the first power supply voltage to supply the scan signal to the scan line in the sleep mode.
 5. The display device with a touch detection function according to claim 3, wherein the control device includes: a gate driver that uses the second power supply voltage to supply the scan signal to the scan line in the normal operation mode, and uses the first power supply voltage to supply the scan signal to the scan line in the sleep mode.
 6. The display device with a touch detection function according to claim 1, wherein, when the touch-detection controller detects the proximity of the object to or the contact thereof with the touch detection electrode in the sleep mode, the control device controls a power supply circuit so as to boost a first power supply voltage constantly supplied from an external device and start generation of a second power supply voltage, and controls the pixel electrode to a predetermined potential using the second power supply voltage and thereafter supplies the touch drive signal to the drive electrode.
 7. The display device with a touch detection function according to claim 6 wherein in the normal operation mode, the control device controls the power supply circuit so as to boost the first power supply voltage to generate a third power supply voltage that is a higher voltage than the second power supply voltage, and uses the third power supply voltage to apply the display drive voltage between the pixel electrode and the drive electrode.
 8. The display device with a touch detection function according to claim 1, wherein in the sleep mode, the touch-detection controller detects the proximity of the object to or the contact thereof with the touch detection electrode using self-capacitance of the touch detection electrode.
 9. The display device with a touch detection function according to claim 1, wherein the touch detection electrode is set as a plurality of pairs, and the touch-detection controller detects, in the sleep mode, the proximity of the object to or the contact thereof with the touch detection electrode using mutual capacitance between a pair of the touch detection electrodes.
 10. The display device with a touch detection function according to claim 1, wherein, when a predetermined gesture performed by the object is detected in the sleep mode, the sleep mode is shifted to the normal operation mode.
 11. An electronic apparatus including a display device with a touch detection function that has a normal operation mode for performing image display and touch detection and a sleep mode for performing touch detection without performing the image display, the display device with a touch detection function comprising: a display area in which a plurality of pixel electrodes are arranged in a matrix on a substrate; a drive electrode that is arranged opposite to the pixel electrodes and is divided into a plurality of portions; a touch detection electrode that is arranged opposite to the drive electrode and forms a capacitance with the drive electrode; a display function layer that has an image display function for displaying an image in the display area; a control device that performs image display control, in the normal operation mode, so as to apply a display drive voltage between the pixel electrode and the drive electrode based on an image signal to exhibit the image display function of the display, function layer, and performs touch detection control so as to supply a touch drive signal to the drive electrode; a touch detecting unit that detects a position of an object in proximity to or in contact with the touch detection electrode based on a detection signal transmitted from the touch detection electrode; and a touch-detection controller that detects, in the sleep mode, the proximity of the object to or the contact thereof with the touch detection electrode, wherein, when the touch-detection controller detects the proximity of the object to or the contact thereof with the touch detection electrode in the sleep mode, the control device controls a voltage between the drive electrode and the touch detection electrode to be substantially zero, and thereafter supplies the touch drive signal to the drive electrode. 